SOUTH Australia's border with Victoria will be closed indefinitely due to Victoria's coronavirus case numbers.

The borders were scheduled to open on July 20, however in the light of Victoria's surge in coronavirus cases, the SA Government has decided to keep the Victorian border closed while considering opening to NSW and the ACT.

SA premier Steven Marshall said his state was "not in a position" to remove its hard border with Victoria as initially planned.

"I know that this is tough, I know there are many families that are dislocated because of the border arrangements," Mr Marshall said. 

"(But) we've got to protect the people of South Australia -- we are not prepared to go backwards."

Victoria recorded 75 new coronavirus cases on Monday and a further 64 on Tuesday.

From Wednesday, South Australia will also introduce an online portal where essential travellers can register and have their border crossing approved before attending a border checkpoint.