Sydney could lose its crown as the biggest city by population to Melbourne if trends continue. But it wouldn’t just be smaller, but potentially older – as the pool of young talent grows in Melbourne.

In 2016, 4.82 million Sydneysiders filled out the census forms compared to 4.49 million Melburnians. Since 2011, more people have been arriving in Melbourne each week than in Sydney – which means this gap is narrowing.

In Sydney, almost every age group has been experiencing a net loss of residents, UNSW demographer and research analyst Alison Taylor said.

Typically, 25 to 44 year olds tend to move more than older residents being of “prime working age and seeking good jobs in the two main jobs markets in Australia,” she said.

But while young people – between 25 to 44 – are moving out of Greater Sydney, there’s not the same number of young people moving in.

Melbourne on the other hand only faced losses of those aged 45 and over.

While further statistics about internal migration will be released in October, she said the reason for the outflow is likely those looking for “affordable housing, better jobs, less congestion and time taken to get to their jobs, better entertainment [and] lifestyle opportunities”.

“Unless you work in a high-paying job, living in Sydney probably doesn’t stack up,” she said.

Arrivals to Greater Sydney by source location, 2015/16 Photo: Alison Taylor, ABS

For Sydney Millennials, this doesn’t come as a surprise.

While many have family, friends and other personal connections to Sydney, at some point the costs outweigh the benefits of staying put.

A median-priced house in Sydney costs $1.15 million, and $718,000 for an apartment. In Melbourne, the median for houses and apartments is hundreds of thousands of dollars cheaper, at $844,000 and $495,000 respectively.

But in Sydney, those leaving the capital tend to opt for the larger regional centres – such as Orange or Tamworth, demographer Glenn Capuano, of consultancy group .id, said.

A lot of Victoria’s growth is also from those leaving the mining states, such as Western Australia, looking for a new city to call home and find a job.

Arrivals to Greater Melbourne by source location 2015/16. Photo: Alison Taylor, ABS

This has contributed to the 2.4 per cent growth rate in Victoria’s population – a booming result that hasn’t been seen in the state “since the 1940s … [and before that] back to the 1880s”.

“[Victoria] gets 60,000 to 70,000 overseas migrants in net terms every year. About 90 per cent settle in Melbourne,” Mr Capuano said.

The driver for this overseas talent into Melbourne, as opposed to Sydney, is similar to the reasons younger residents move – the cost of living, Domain Group chief economist Andrew Wilson said.

​”Sydney has a burgeoning economy but it’s very difficult to find rental accommodation and rent is 30 per cent higher than Melbourne,” Dr Wilson said.

“It’s about weighing up better job prospects in Sydney versus costs for accommodation.

“Sydney is getting to a stage where we’re full up. That’s what prices are doing – making us an elite, prestige market with high barriers to entry.”

But Melbourne’s median house price is expected to reach $1 million by the end of next year with property price growth is outpacing Sydney’s.

This could see migrants, and younger Australians, look to Brisbane instead, Dr Wilson said.

In addition to being cheaper, Melbourne has the additional bonus of being culturally attractive, Compass Economics chief economist Hans Kunnen said.

Between 2005/06 and 2014/15, the Australian Bureau of Statistics records Sydney’s net interstate annual average growth to be a loss of 16,017 people and Melbourne’s to be a gain of 2885.

“Sydney needs better transport and cheaper housing. It is well behind Victoria on both,” Mr Kunnen said.

Land release, a quicker turnaround on development projects and more urban infill supported by infrastructure would “change the story for Sydney”, he said.