Reverend David Powys feels the pain of the people in Cranbourne.

Working parents in the fast-growing south-east spend hours commuting to and from work, time that could be spent with their children.

"The kids live isolated lives because their parents aren't around much, which means they spend a lot of time behind closed doors, watching screens," the vicar of St John's Cranbourne said.

Cranbourne East vicar David Powys is agitating for better public transport. Joe Armao

"They're getting up very early in the morning to go to the city for work and getting back very late. It's all about sleeping, commuting and working.

"I feel the pain of my people."

As Melbourne's population continues to boom, public transport services are struggling to keep pace.

Mr Powys recently hung a "protest painting" outside his church in the marginal seat that depicts an abandoned stretch of rail track to Cranbourne East, which is not serviced by train.

Labor and the Liberals are promising to upgrade the Cranbourne line, but Mr Powys noted that trains were promised to Cranbourne East "20 years ago".

David Powys with his protest painting. Joe Armao

His protest comes as new research reveals that 1.4 million people in Melbourne's outer suburbs are without proper access to public transport, more than anywhere else in the country.

About 62 per cent of those on the city's fringe do not live within walking distance of frequent public transport.

Illustration: Matt Golding

It is worse than Sydney, where 1 million people or 42 per cent of the outer suburban population live far from frequently running trains or buses.

Yet the findings - detailed in a fresh report by the nation's infrastructure adviser, Infrastructure Australia - reveal that Brisbane has the highest proportion of people with inadequate public transport access.

There, 80 per cent of residents in the outer suburbs, 1 million people, live far from public transport, compared with 52 per cent in Adelaide and 50 per cent in Perth.

Infrastructure Australia's Peter Colacino warned that public transport access in Melbourne's outer areas was among the worst in the country.

One problem was urban sprawl, he said, but a key factor was the city's public transport network is not big enough to reach people living on the fringe.

"It is the case that urban sprawl is creating that challenge, but the rise of that challenge is no greater in Melbourne than in other places.

"The cause therefore, must be the amount of public transport that's available. There is a gap around the provision of public transport in Melbourne."

For people living in the outer suburbs – close to half of Melbourne's population – this means poorer access to jobs and education, according to the report released on Friday.

It also means a greater dependence on a car, which drives up household costs.

The report called on state governments to be creative in delivering public transport to far-flung suburbs.

Building new trains and bus routes is expensive, so transport departments should partner with ride-share companies and launch on-demand bus services, the report found.

Victoria was more cautious than other states in experimenting with on-demand services to plug gaps in the network, he said.

Transport for Canberra has partnered with Uber to extend the reach of the city's late night bus service under a series of trials.

The organisations jointly subsidised a $10 discount on Uber rides that were taken between bus stops and surrounding suburbs.

The NSW government is also trialling on-demand bus services.

Public Transport Minister Jacinta Allan said $20 billion was being spent on public transport in the outer suburbs.