LEIGH SALES, PRESENTER: Tonight, we are bringing you the first in a special three-part look at an issue that seems to underpin many of our national anxieties: population.

Immigration, the economy, housing, congestion - they all come down to how many people live here. Australia's population growth has radically changed our country during the past few decades.

It is influenced by things such as the number of people moving permanently to Australia, a falling birth rate and an ageing population.

For the next three nights, 7.30's Andy Park is taking a look at how these forces are changing our cities, our suburbs and our regions.

Tonight, we start in the suburbs to chart the health of the great Australian dream.

ANDY PARK, REPORTER: The way we are headed, the Australia you grew up in won't be the Australia you retire in.

30 per cent of us weren't even born here anyway.

We are a big land with a small population and that is changing faster than anyone predicted.

We are 25 million now, but by the middle of the century, that number will grow to more than 40 million.

Just think, 400,000 new people each year. Where are they going to live? How are we going to feed and water them?

GUEST: When you are one drop short in a city like this, you have got an emergency. You can't do with water what we do with roads. You can't play catch-up.

ANDY PARK: Just how are we going to fit them in?

PROFESSOR BRENDAN GLEESON, MELBOURNE SUSTAINABLE SOCIETY INSTITUTE: We need that as a national conversation. We don't have it at the moment.

ANDY PARK: Two-thirds of our population growth comes from overseas migration because we are simply not having babies like we used to.

ABUL RIZVI, IMMIGRATION DEPARTMENT,1990-2007: More than 3.6 million migrants, that is one in seven people in the country, have arrived in the last 20 years.

ANDY PARK: Our cities draw almost 90 per cent of migrants, adding to the squeeze on housing and on roads. In the last 25 years, the fast-growing outer suburbs have already doubled in population.

DICK SMITH: Look at this down here. This is just jammed and that is the whole of Australia.

ANDY PARK: Some say we need to stay small or at least slow down to maintain the lifestyles that we have.

LEITH VAN ONSELEN, ECONOMIST: There isn't any consideration about what the long-term impacts are going to be on livability and really Australia is marching blind.

PHIL RUTHVEN, ECONOMIS AND SOCIAL FORECASTER: There is no doubt in my mind that Australia is underpopulated by any definition you are likely to have.

ANDY PARK: Others say that this record level of growth is essential to propelling us into the future of a big Australia.

PROFESSOR ANN EVANS, AUSTRALIAN NATIONAL UNIVERSITY: In 2050, there are going to be far more opportunities for everyday Australians. The types of workplaces that we have are changing. The types

of ways that we commute and the way that we live are changing. The ways that we start relationships are changing.

ANDY PARK: This is Mickleham, Australia's fastest-growing area in Australia's fastest-growing state.

Apart from clogged roads or packed buses, Australia's explosive growth manifests in a series of often submerged ways.

For our smallest Australians, there is already a 6-month it watching list for these learn-to-swim classes in nearby Craigieburn. In a huge new facility, the local council only opened a year ago.

Have you noticed how quickly this area has grown?

BELINDA WOOD, MICKLEHAM RESIDENT: It has. It has grown very, very fast. The demand for schools and resources and facilities like this is unbelievable. Childcare, there is quite a long waiting list. I think we waited 18 months to get a position for one day.

ANDY PARK: But here too, are contrasting views on just how big Australia could or should be. So there is room for a big Australia?

ETHAR OWRAHA, MICKLHAM RESIDENT: Yes, yes. If you get another 100 million people you can fit them here because Australia is still big mate.

Maybe all of us live in 10 or 15 per cent of the Australian map.

ANDY PARK: What do you hope Australia will look like for your daughter?

BELINDA WOOD: I hope it's not that dissimilar from when I was growing up.

ANDY PARK: But the lives of these Australians won't resemble their parents.

GEOFF PORTER, MAYOR, MICKLEHAM: When I was a young fella growing up, there was none of this here. It was just open paddocks, horses, cows, rabbits running around everywhere and now to look at the change and the development that has occurred it is just amazing.

ANDY PARK: Rightly or wrongly, the frustrations of locals are often aimed at the most visible for of government. How many people are coming into your municipality every year?

GEOFF PORTER: We estimate at the 10,000 mark. I suppose the frustration of local people would be, well, how far do I have to travel to get my two litres of milk and loaf of bread?

They come also with the understanding that there is not going to be a tram outside their front door.

VOICEOVER: This type of housing development is typical of Australia — one house to about a quarter acre of land.

BRENDAN GLEESON: Australia was the first suburban nation. We embraced the suburban living with great fervour. Most Australians still live in suburban settings and prefer to do so, but our suburbs now face development and planning pressures.

VOICEOVER: It seems if there is a solution, we must find it in our own backyard.

ANDY PARK: Brendan Gleeson is the director of the Melbourne Sustainable Society Institute and he says the days of a quarter acre block close to the city with easy public transport and amenities are long gone.

BRENDAN GLEESON: I think we can see that in some of the political and popular discussions going on that people are really feeling it. Promises of public transport, of health and education facilities, that are really on the never-never.

ANDY PARK: Cheap housing, green fields and state developments are the latest chapters in Australia's urban sprawl transforming our entire notion of Australian suburban life. Doubling in population in the last 25 years, these outer suburbs are now home to one in five Australians. They account for 11 per cent of GDP and are growing at twice the rate of the rest of the country.

There are more workers in suburbs like Mickleham than there were a decade ago, but, you see, there are only about the same amount of jobs. In some cases more than half a population of these dormitory suburbs clear out for work on any given day, putting extraordinary stress and strain on roads and transport and making congestion the most visible sign of Australia's frantic pace of growth.

Economist Leith Van Onselen says we are nowhere near ready for a big Australia.

LEITH VAN ONSELEN: This is one of the big fallacies of rapid population growth. There is this notion that you can just plan for it and we just need to build the infrastructure, but the problem is in built-out cities lick Sydney and Melbourne, where there isn't any additional space, building out infrastructure is incredibly expensive.

ANDY PARK: In fact, the Productivity Commission in 2013 warned that for infrastructure to keep up with population growth over the next 50 years, we would need to spend five times what we have spent in the last 50 years. Nowadays Melbourne's urban sprawl is propelled north by developers at a blistering speed.

ANN EVANS: This adds a lot to the stress of people's lives. You hear a lot of people talking about wanting to spend that time with their families or doing other things than sitting in a car.

ANDREW CINI: You can see it is terrible and it gets worse down there.

ANDY PARK: Andrew Cini is one of thousands pouring in, pushed out by housing affordability, pulled in by 5 per cent deposits on house and land packages if you can get in early.

ANDREW CINI: I paid about $500,000 for a five-bedroom, three-bedroom house on about 576 square metres of land. There is no infrastructure. You are buying at probably the cheapest point. History tells us anything, it is like planning a fruit tree. You plant the fruit tree, you water it, it grows and you reap the rewards.

PHIL RUTHVEN: Many of them because they are astute investors are investing in dwellings either in places like Milton outside of Melbourne or Craigieburn where you can buy a home quite cheaply and pay it off.

Young people are having a very different approach to where they want to live and how they are going to manage their financial affairs.

ANDY PARK: This is your Australian dream, Andrew?

ANDREW CINI: That is it.

ANDY PARK: It is an incomplete dream.

ANDREW CINI: It is quite incomplete, isn't it?

ANDY PARK: Do you think this level of growth is sustainable?

ANDREW CINI: Probably not, no.

ANDY PARK: Even though you are part of it?

ANDREW CINI: I am part of it. We've had immigration and that sort of stuff occur forever, you know, that is what Australia is built on. It is sustainable, but if it is controlled definitely.

ANDY PARK: So your mindset is to get in while there is still green fields and land to be developed because it will run out?

ANDREW CINI: Yes, definitely. It can go right up to Sydney. Who knows when it will stop.

ANDY PARK: Nearby, a young family is also moving in.

DARREN YOUNG: We have got all sorts of cultures, particularly in this street. There is Brazilians next door, Italians. We have got Sri Lankans. I think it is great.

ANDY PARK: Darren Young's family are six weeks into their huge new dream home. They are some of the 18,000 people moving from Victoria to interstate helping to make Melbourne's population almost as big as Sydney's.

Is this the last box, hopefully?

DARREN YOUNG: I am hoping so. It has been a massive unpack.

ANDY PARK: But so bad is the dust kicked up by ongoing construction, they can't dry their clothes outdoors driving up their energy costs.

What are the biggest headaches about living in an area growing so quickly?

DARREN YOUNG: I think the biggest problem is a lack of infrastructure. It is a great area, but there is not a lot out here at the moment. The only thing we really have got is a service station.

ANNA CHAU, INFRASTRUCTURE AUSTRALIA: Population growth is really an opportunity for us to really embrace however that means actually addressing the challenges that might be emerging from it.

Population is really the main driver for demand for transport, for water, for energy, for telecommunications.

ANDY PARK: Enrolments for the local primary school have doubled here in the last two years. Darren's preference for a Catholic school in his community is not yet an option.

DARREN YOUNG: It's 25-30 minutes to Craigieburn from here. It is going to be a bit of a hike for us until we get set up. A school in the area would be nice.

ANDY PARK: Outer suburban growth areas received 35 per cent of Australia's population growth, but only 13 per cent of federal infrastructure funding.

STUDENT, CRAIGIEBURN: I think my favourite thing at school is maths. Drawing. Sports.

ANDY PARK: This area is growing in more ways than one. It has taken almost 5000 of the Federal Government's 12000 Syrian humanitarian arrivals, like young parents, Gina and Ashwar.

GINA KHOSHABA: We have small children and when there is an emergency at night the doctors are closed. There are things we need because the population is growing, it keeps getting bigger but the thing that is lacking is a hospital.

ANDY PARK: They are Mon the 35 per cent of local residents born overseas.

ABUL RIVZI: Whilst the media and the public were transfixed by the 63000 asylum seekers arriving by boat, we had over 3.6 million people arriving via planes to Australia, which transformed Australia in terms of its age composition, in terms of its skill composition and in terms of its ethnic composition.

ANDY PARK: For those on Australia's suburban frontier, it is about pegging out their patch of green fields while the fields are still green.

ANDREW CINI: I do feel like a bit of a pioneer. (LAUGHS)

ANDY PARK: As our population hurtles towards 45 million by the middle of the century, this is the engine room of our boundless growth.

Today is kind of a big day really.

ANDREW CINI: Definitely. Got the key, ready to...

ANDY PARK: This is the key to your first home.

ANDREW CINI: Yes.

ANDY PARK: What does this mean to you to have this house?

ANDREW CINI: Oh, mate. People say they create their memories and their dreams in a house. What will this house bring me? Master bedroom in here. Kitchen area.

ANDY PARK: Wow.

ANDREW CINI: You could fit a family in here quit easily.

LEIGH SALES: That story produced by Paige Mackenzie and tomorrow night in the second part of our series, we will look at growth on the fringes of our major cities, the so-called urban sprawl.