More than 5,000 Australians are undergoing mandatory quarantine in hotel rooms and other accommodation around the country.

Key points: People who had been overseas account for around two thirds of Australia's known cases

People who had been overseas account for around two thirds of Australia's known cases Most people are being held in New South Wales, followed by Victoria

Most people are being held in New South Wales, followed by Victoria The NSW Police Commissioner has said some travellers' complaints are reasonable and will be dealt with

State and territory leaders agreed to forcibly isolate returning overseas travellers in hotels for 14 days from midnight on Saturday.

The tough measure was adopted by the National Cabinet after health authorities warned people who had been overseas accounted for about two thirds of Australia's known coronavirus cases.

Since the controversial measure came into effect, the Department of Home Affairs has confirmed more than 5,500 people have returned to Australia.

The largest number of people is being held in New South Wales, with more than 3,140 travellers arriving at Sydney International Airport since Sunday, according to figures as of 11:00am on Wednesday.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 17 seconds 2 m 17 s Quarantined Kate takes us on a tour of her hotel room

NSW more than 3,140

NSW more than 3,140 QLD more than 520

QLD more than 520 VIC more than 990

VIC more than 990 WA more than 830

WA more than 830 NT less than five

The measure has received mixed responses, with some cooped-up travellers expressing frustrations about not being able to get fresh air or outdoor exercise.

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On Wednesday morning NSW Police Commissioner Mick Fuller said state authorities were anticipating another 700 people to arrive from overseas throughout the day.

He also confirmed he was working to rectify some of the concerns raised by hotel-bound Australians.

"I spent most of yesterday reviewing our process around health, welfare and security and over the next 24 hours we will certainly improve those," he said.

"I know there are people who are posting on social media their dissatisfaction … some complaints are reasonable and we will deal with those.

"We shouldn't frame everyone in these hotels as people who are ungrateful because it certainly is not the case."