Australia's new Prime Minister, Mr Scott Morrison, is considering a migration overhaul, which will include limiting flows of migrants, and possibly international students, to the country's congested cities.

Mr Morrison, who replaced Mr Malcolm Turnbull last month, reportedly plans to require some migrants to live outside Sydney or Melbourne for up to five years.

He has indicated that different rules could apply to different cities and regions across the country to encourage migrant flows to areas most in need of skills or more people.

Last year, about 87 per cent of skilled migrants to Australia settled in Sydney or Melbourne, cities with about five million people each.

The new arrivals helped to boost the population of Sydney by 100,000 and that of Melbourne by 125,000. In contrast, the population of Adelaide, which has 1.3 million people, grew by 9,600.

These variations come amid calls to curb population growth in cities such as Sydney and Melbourne to address congestion, transport problems and housing affordability.

The new Population Minister, Mr Alan Tudge, said the problem is not Australia's growing population, which hit 25 million recently, but how the growth is distributed.

87% Skilled migrants who settled in Sydney or Melbourne last year.

Transport facilities and infrastructure development have not kept up with the influx of migrants in some cities, he said.

"Where we can do better is to try to get a broader distribution of migration rather than nearly all migrants going to Melbourne and Sydney," he told The Australian.

Mr Morrison, who is from Sydney, has pledged to address concerns about population pressures in larger cities.

He said the government's efforts to slow the number of migrants to certain areas could potentially extend to international students.

"There is no case for it in Adelaide, there's no case for it in Perth, there's no case for it in Hobart or James Cook University (in Queensland)," he told The Sydney Morning Herald. "But there could be a case for it in Melbourne or the University of New South Wales or UTS (University of Technology, Sydney)."

Australia has a skilled migrant programme which has helped to plug labour shortages and fuel economic growth. But numbers have slowed amid a growing public debate about urban congestion.

In 2016-17, it received 183,608 permanent migrants, 67 per cent of whom were skilled migrants. Most of the others were family members of residents. About 21 per cent of migrants were from India, 15 per cent from China and 9 per cent from the United Kingdom. About 1,500 permanent migrants came from Singapore. The number of migrants in 2017-18 fell to about 162,000, according to media reports. Official data is yet to be released.

The government already has special types of visas for migrants willing to move to rural areas.

Earlier this year, Mr Tudge, who was the minister in charge of citizenship at the time, said he wanted to introduce minimum time limits that migrants must spend in rural areas as there were concerns that some who had arrived on special visas quickly moved to bigger cities.

But critics believe such efforts to impose tight curbs on migration flows will be hard to administer and could affect the economy.

"I'm not sure that mandating new immigrants living in regional Australia is going to work," Labor MP Richard Marles told Sky News. "I'm not actually sure there is the power to put that in place, to actually mandate that they do live there."

Business groups have urged the federal government not to limit migration numbers, saying the solution to population pressures is to build better roads and public transport facilities and to plan for urban housing needs.

But some regional areas are not waiting for the government to find ways to boost numbers.

The Northern Territory said last month it would offer up to A$15,000 (S$14,800) over five years to people from around Australia to move there to take up "high-priority jobs" as accountants, mechanical engineers and chefs. It is also considering boosting schemes to attract skilled migrants.

"The welcome sign is up in the Northern Territory," said its Chief Minister, Mr Michael Gunner.