Western Australia has recorded one new local coronavirus infection in a woman who came into brief contact with a previous case.
Premier Mark McGowan says the 32-year-old had visited a gym in Perth and had only minimal contact with the previously known case, a WA woman who had visited Sydney.
Mr McGowan has also released a number of potential exposure sites, including the gym, a dog grooming centre and a supermarket.
"This is a concerning development. It demonstrates just how quickly this variant can spread," the premier said.
Health officials are currently tracking down the woman's known close and casual contacts.
They have already identified 114 close contacts for the returned traveller and 27 of those have returned a negative COVID-19 test so far.
Regarding workers who returned from a Northern Territory mine, Mr McGowan said 177 people who'd been at the site during the infectious period had been identified and were in isolation.
So far, 149 had tested negative in what the premier described as encouraging results.
The new virus case in WA came after the state announced stronger border restrictions on the Northern Territory, Queensland and the ACT.
From 6pm on Sunday, travellers from those jurisdictions have been deemed "low" risk, meaning they must get tested and self-isolate for 14 days after arriving in WA.
A hard border was on Wednesday reimposed in WA for NSW residents, currently in lockdown due to the growing Bondi cluster.
