The Australian state of New South Wales is to charge travellers for quarantine.
A family-of-four returning from overseas will have to pay A$5000 ($5287) for their hotel quarantine stay.
NSW Premier Gladys Berejiklian has told travellers: "It is only fair that they cover some of the costs."
The state government will start charging international travellers for their mandatory hotel accommodation from 12.01am this Saturday (July 18). Fees are set at A$3000 ($3172) for adults and A$500 ($528) for children over 3.
The new costs will cover daily meals and accommodation.
At the end of their 14-day lockdown, travellers will receive an invoice to pay within 30 days.
Berejiklian said mandatory hotel quarantine had been instrumental in reducing the spread of Covid-19 in NSW.
"NSW is the gateway to Australia, with more than 35,000 Australian citizens and permanent residents returning from overseas processed through our hotel quarantine system since 29 March 2020," she said.
"The NSW taxpayers have footed much of the bill so far, with more than $65 million spent on quarantine accommodation to house international travellers returning to Australia.
"Australian residents have been given plenty of time to return home — and we feel it is only fair that they cover some of the costs of their hotel accommodation."
Australian travellers who have purchased plane tickets before midnight tonight (July 12) will be excluded from the new fees.
The state government will continue to fund security, transport and logistics. Hardship arrangements will be available for travellers unable to pay.
Travellers will be automatically directed into hotel quarantine.
Stuart Ayres, the minister responsible for hotel quarantine, said housing large numbers of international travellers returning to Australia "posed a major logistical challenge. However, it's one that has been successfully managed".
"Over the past few weeks, the majority of new Covid-19 cases in NSW have come from overseas travellers in hotel quarantine," Ayres said.
"NSW police, NSW health officials and the accommodation industry will continue to work together to provide the nation's leading hotel quarantine system."
The new fees come after Prime Minister Scott Morrison announced on Friday that all states and territories would move towards charging people for the cost of mandatory quarantine, with the number of international arrivals to be slashed from this week.