Mr Marshall has insisted that SA will not lift quarantine requirements for anyone arriving from Victoria if it is not safe to do so.

Under current arrangements, SA is due to lift those measures on July 20.

"So we've still got three weeks, but that is now under a cloud," the premier said on Monday.

"We will look very closely at this and update the people of South Australia as soon as we possibly can.

"We are very concerned about the numbers coming out of Victoria at the moment, there's no doubt about that."

Victoria reported 75 coronavirus cases on Monday after revealing 90 new infections over the weekend.

Police Commissioner Grant Stevens said he would take advice from the experts in SA Health in relation to the efforts in Victoria to contain the virus and to properly establish the extent of the spread into the Victorian community.

"The reality is, the numbers we're seeing today relate to activities that occurred over the last two weeks, so we may see a much better performance from Victoria over the next few days," Mr Stevens said.

"It's important to everybody that Victoria gets this under control."

From Wednesday, SA is also moving to a pre-approval system for all people entering the state as part of ongoing COVID-19 restrictions.

Anyone wanting to come to SA by road or air will need to apply through an online form, a process officials say will speed up access at the state's borders.

People arriving from Queensland, Western Australia, Tasmania and the Northern Territory will not be required to quarantine, but 14 days of isolation will continue for anyone from NSW, Victoria and the ACT.

SA reported no new coronavirus cases on Sunday, taking the state's run of days without a new infection to more than a month.

However, 250 repatriated Australians arrived in Adelaide from India on Saturday and local health officials have warned that could result in some new cases.

Australian Associated Press