AS the number of coronavirus cases around the world heads towards 10 million, in Australia there is still concern with developments in Victoria which has had a dramatic increase in cases of COVID-19 in the past fortnight.

A total of 90 cases were reported in Victoria this weekend — 41 new cases on Saturday and 49 on Sunday, the highest daily number since April.

Mildura has not had a new active case since April.

Victoria has stepped up measures to contain the outbreak.

Premier Daniel Andrews on Sunday announced returned travellers will now need to be tested twice before being allowed to leave quarantine, or they will have to spend a further 10 days in quarantine.

But he also announced that the less-invasive saliva testing would start on Sunday.

"I think what's driven the reticence of some parents to have their often very small children tested is that it is not a pleasant procedure," Mr Andrews said.

"But with the saliva test coming on board ... I think we'll be able to get the numbers right up to 100 per cent."

Mr Andrews also flagged the government could consider locking down specific suburbs if necessary, but it wasn't needed yet.

South Australian Premier Steven Marshall said there was a real concern about the very significant hotspots in metropolitan Melbourne.

"It is still a nasty disease," he said.

"I don't think we're going to be really back to normal until a vaccine is found. We are going to have to to live with this disease right across the world."

There are 7641 confirmed COVID-19 cases across the country, where the pandemic has killed 104 people.