South Australia will close its border to Greater Melbourne from 6PM tonight after the Victoria’s Whittlesea cluster recorded a 15th case earlier today.

The restrictions will be put in place from 6PM this evening. South Australians returning from greater Melbourne after the 6PM cut off will be expected to “subject themselves” to 14 days of quarantine.

Essential travellers with permits will be the people exempt from the border closure.

SA Premier Steven Marshall also added that anyone returning from Greater Melbourne after May 20 “will need to undertake a range of testing.”

“”In fact, testing one day one, five and 13 and again after that first test is taken; they will need to go into isolation pending a negative result coming in,” Mr Marshall said.

Chief Health Officer Professor Nicola Spurrier was unable to predict how long the SA border would be closed to Melbourne residents.

“It’s very difficult to predict at the moment because it’s obviously an evolving situation and we are getting updated as things evolve over in Victoria, so it’s too early to say.

“Obviously we would want to have it as short a time as possible and we are absolutely hoping that Victoria, with their fantastic contact tracing, get their primary secondary contacts into quarantine quickly and get that wrap around.”