Western Australia will set up a new quarantine hotel and may reduce elective surgery to cope with an influx of returned travellers.
Australia's weekly returned traveller cap will rise from 4000 to 6000 after all states reach new limits over the next month.
From September 27, Western Australia will increase its arrivals by 200 per week before adding an extra 300 from October 12.
Premier Mark McGowan strongly pushed back against Prime Minister Scott Morrison's initial plan to up the cap by 2000 next Friday.
"Recklessly doubling the number of arrivals into Western Australia overnight is not the way we should be approaching this issue," he told reporters on Friday.
"Hotel quarantine is not simply about available beds. It's about the capacity of qualified people to provide medical support, security and police services.
"I do not want to reduce the standard of our hotel quarantine system. We desperately do not want to see what happened in Melbourne happen in Western Australia."
Mr McGowan was pleased with the compromise reached during Friday's national cabinet meeting which includes additional Australian Defence Force support for the state.
"This gives us a lot more time to work out ways of managing additional people, Australians coming home from overseas," he said.
"It basically gives us three and a half weeks as opposed to one week."
Mr McGowan said at least one and possibly two extra quarantine hotels would need to be stood up to accommodate the extra 500 returnees.
A revival of the quarantine program on Rottnest Island isn't required.
WA has enlisted eight hotels to house people returning from overseas and Victoria, as well as airline staff.
Elective surgery may be impacted by the change to ensure medical support isn't compromised for the increased hotel quarantine efforts.
"I don't want to reduce elective surgery capacity but it may be necessary," Mr McGowan said.
It comes as a 35-year-old Secret Harbour man was fitted with an electronic monitoring device over alleged breaches while self-quarantining at a Redcliffe hotel.
The man arrived on a Queensland flight on September 8 and later allegedly twice invited a woman into his room and the left the hotel to attend a small party.
He has been transferred to a quarantine hotel in Perth's CBD and had his ankle fitted with the tracking device ahead of facing court next week on four charges of failing to comply with a direction.
Meanwhile, WA announced it will start testing wastewater for COVID-19.
Health Minister Roger Cook on Friday said the state's sewerage network would start being tested for the virus within the next month.
The testing aims to identify the existence of the virus to enable more targeted campaigns encouraging people to be tested.
The WA government also unveiled a $3 million fund to support the state's travel agents.
Agents will be eligible for support packages of up to $10,000 under the scheme.
There were no new COVID-19 cases recorded in WA on Friday, with active cases dropping to three.
