More than 400 people in the ACT had declared that they'd recently visited Western Australia's Perth and Peel regions as of Monday afternoon.
An ACT Public Health Notice came into effect on Sunday evening, directing that any person who was already in the territory and had visited Perth and Peel in the last fortnight declare as much by 6pm on Monday.
If they weren't already in the ACT, they had to declare that they'd visited Perth and Peel within 24 hours of them coming back into the territory.
Of the more than 400 people in the ACT who'd made a declaration as of 4pm on Monday, 90 had arrived in Canberra after a flight from Perth about 7pm on Sunday evening. They were met at the airport by ACT Health staff.
A further 14 passengers on the flight travelled on to NSW, so they completed that state's entry form.
ACT Chief Health Officer Dr Kerryn Coleman said on Monday morning she wasn't aware of anyone who was in quarantine in Canberra because they'd visited a COVID-19 exposure site in Western Australia.
An ACT government spokeswoman said as at 4pm on Monday, no close contacts of coronavirus cases had been identified in the ACT.
People who had visited an exposure site on or after April 27, or a close contact exposure site before April 27, had to immediately quarantine for 14 days, get tested for coronavirus and contact ACT Health.
"We're just collecting information and asking you to declare that you haven't been to any of the exposure sites," Dr Coleman said.
"If you have, we need you to go into quarantine, get tested, and let us know."
The government spokeswoman said 354 people who had arrived in Canberra on flights from Western Australia since April 27 had been advised to complete a self-declaration form and check the Western Australian government's website for new exposure sites.
ACT health authorities on Sunday urged Canberrans against travelling to Western Australia, and said any non-ACT residents who'd been to a close contact exposure site could not enter the territory without an exemption.
West Australian Premier Mark McGowan said that, as at 8am on Monday morning, the state had recorded no new local cases of COVID-19, but it had recorded three cases in hotel quarantine.
A hotel quarantine security guard in Perth tested positive to COVID-19 on Saturday.
A further two cases were detected in housemates that lived with the security guard.
The housemates worked as food-delivery drivers, with a number of locations identified as public exposure sites.
Mr McGowan said on Sunday a lockdown was not needed, but said it was an option if the situation got worse.
The additional cases did, however, force a ban on crowds at the local derby AFL match between the Eagles and Dockers, which was set to play out before 45,000 fans at Optus Stadium on Sunday afternoon.
Perth and the Peel region had only just emerged from a three-day lockdown in late April after transmission of the virus leaked out of hotel quarantine.
- With Andrew Brown.
Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: