Prime Minister Scott Morrison says the nasal swab test for coronavirus might be uncomfortable for returned travellers, but the alternative is longer quarantine.

Returned travellers in quarantine have a clear choice: get tested for coronavirus and get out, or spend more than a week longer in isolation.

Victoria has moved to ensure people in mandatory hotel quarantine are tested to make sure they don't have the disease before being allowed back into the community.

Those who refuse tests will have to spend an extra 10 days in quarantine.

The move comes after it emerged three in 10 people in Victorian quarantine were refusing tests - a much higher rate than in other jurisdictions.

"You have two choices: you can stay longer or you can have a test," Prime Minister Scott Morrison said on 2GB radio on Monday.

"That test, the throat and nasal one, it's a bit unpleasant for a few minutes but they're also trialling another saliva test down there."

The new saliva test, a world-first, has been developed by the Doherty Institute.

Deputy Chief Medical Officer Nick Coatsworth said the institute was effectively doing real-time testing of the new tests, which may be slightly less accurate than the nasal and throat swabs.

It was part of an unprecedented effort to contain the urban outbreaks, he said.

Victoria recorded 90 new cases of the virus over the weekend, and a double-digit increase for 12 days running.

The majority of the weekend's cases were locally acquired.

The latest figures contrast with Western Australia, which had one new case and NSW with three - all in people returning from overseas.

Other states had no new cases.

Dr Coatsworth said medical officials were considering whether to recommend people in Melbourne wear masks when out in public.

The expert health committee considers its position on masks every week.

"Certainly in the bulk of Australia at the moment, they will be of no use at all," he told ABC TV.

"Even in Victoria, where the numbers are modestly increasing, their use may be questionable.

"But certainly, if there is a place where we are looking to see whether masks should be recommended, it's down in Victoria."

At the moment, the official health advice is that if people feel more comfortable wearing a mask, especially on public transport, they should do so, but it is not widely recommended.

The Victorian government is conducting a testing blitz in an attempt to prevent further spread of the virus, which prioritised the suburbs of Broadmeadows and Keilor Downs at the weekend.

About 40,000 people have been tested since Friday.