Western Australia has detected two new local COVID-19 cases linked to an infected French backpacker who travelled from Queensland.

The new cases are close contacts of another recent infection and are in hotel quarantine, WA Health said on Saturday.

This takes the total number of cases linked to the so-called "backpacker outbreak" to 16, and includes the unvaccinated 25-year-old index case.

Many of the cases went to a busy Perth Mess Hall dance party with about 400 other people on December 19, many from the traveller community.

More than 770 close contacts have been identified, with 18 yet to be tested as police struggle to track down some backpackers who are thought to have left WA or are avoiding testing.

One new infection among returned travellers has also been identified.

They are in hotel quarantine.

Meanwhile, WA has moved both Tasmania, which jumped from 520 active COVID-19 cases to 938 on New Year's Day, and the ACT, which increased by 448 cases to a total of 1479, from medium risk to high risk.

This means that, from Monday, anyone entering the state from the ACT or Tasmania must be fully vaccinated, take a PCR test within 24 hours of arrival and take another test on day 12 of their 14-day self-isolation.

They must also use the G2G Now app while in quarantine.

More than 92 per cent of Western Australians had received their first COVID-19 vaccination, Health Minister Amber-Jade Sanderson said.

There are now 35 active confirmed cases in WA.