The Australian government has unveiled a proposal to force new migrants to live outside Sydney and Melbourne.
The policy would aim to ease congestion in Australia's two biggest cities while boosting regional areas, Population Minister Alan Tudge said on Tuesday.
The government may introduce visa conditions to limit where some migrants live for up to five years, he said.
However, some experts have questioned whether the idea is enforceable and likely to achieve its goals.
Why is Australia having this debate?
Currently, about two-fifths of Australia's 25 million people live in Sydney and Melbourne.
Though Australia's population growth rate ranks 77th globally, according to the World Bank, it is high among OECD nations - rising by 1.6% last year.
The growth has been driven largely by migration, with most people settling in Melbourne, Sydney and south-east Queensland, according to the government.
That has contributed to infrastructure and congestion problems, with Melbourne and Sydney each expected to exceed eight million residents by 2030.
What does the government say?
"Settling even a slightly larger number of new migrants to the smaller states and regions can take significant pressure off our big cities," Mr Tudge said in a speech on Tuesday.
The proposal is not detailed at this stage, but such visas could carry a "geographical requirement... for at least a few years".
Other incentives would also be offered, Mr Tudge said, in the hope that migrants would remain in regional areas permanently.
Such visa restrictions would not extend to migrants on family reunion or employer-sponsored visas, he said.
The Labor opposition said the idea should be considered, but raised concerns about its lack of detail.
Would restrictions work?
Immigration and population experts told the BBC that such measures would not necessarily reduce congestion in cities.
"There is a strong argument for the government to redirect new migrants to the bush... but there needs to be sufficient employment for them, and that's the big Achilles heel of the whole idea," Prof Jock Collins from the University of Technology told the BBC.
Prof Peter McDonald, a demographer at the University of Melbourne, said the issue extended beyond migration.
"In Australia, the population growth has run ahead of infrastructure - we have been slow to put in the appropriate systems such as public transport networks that are needed for large cities."
And former Australian Border Force chief, Roman Quaedvlieg, questioned whether the policy could be enforced.
Imposition of the visa condition is the easy part. Enforcement will be harder. Migrants will gravitate to opportunities & amenities in cities. It’s not possible to police the condition without substantial resources, both identifying breaches & sanctioning them. https://t.co/eOawmwNRSz— Roman Quaedvlieg (@quaedvliegs) October 8, 2018
However, said Prof Collins, research showed that migrants had thrived in smaller communities with strong employment.
"Most of them have really liked living there in the bush, and said they had a warm welcome," he said.