An announcement on the relaxation of Melbourne’s COVID-19 restrictions is expected within 24 hours.

Restriction changes are likely to come into force at 11.59pm on Thursday, but it’s not yet known which rules will be removed and which will stay.

Director of Health and Biosecurity at CSIRO, Dr Rob Grenfell, says he “would suspect that we will still have some restrictions”.

He says the “concern” is that we may be starting to see the virus establish itself in Melbourne.

“What it appears, with some of these mystery cases, is that there’s some unknown circulation going on,” he told 3AW Breakfast.

Dr Grenfell says it’s inevitable that COVID-19 eventually establishes itself here, and that’s why vaccination must be the priority.

“The virus will come in whether we let it in or it comes in by itself,” he said.

“It’s ultimately going to establish itself in this country, we can’t ignore that fact.”

Dr Grenfell expects masks will remain in place in some settings for a long time yet.

“I do think masks will become part of our lives over the next number of years,” he said.

Press PLAY below to hear more on how Dr Grenfell thinks the COVID-19 situation will develop in Australia