A COVID-19 vaccine hub will be opened on Kangaroo Island with help from the Royal Flying Doctor Service as SA officials monitor two new infections in Melbourne.

Recent travellers from Victoria to South Australia have been urged to check for updates on potential exposure sites after the discovery of two probable COVID-19 cases in Melbourne's north.

The Victorian Health Department was notified of the two probable cases on Monday morning with the infections understood to be connected.

South Australia's Chief Public Health Officer Nicola Spurrier said she had received a briefing from Victorian officials and expected more information to be provided later on Monday.

"I'm just working through the implications of that. Victoria's contact tracing team are obviously doing an excellent job," she said.

Prof Spurrier said the cases were a reminder that even though Australia had done well in containing the virus, the potential for a significant outbreak remained.

Premier Steven Marshall said while SA was concerned by the situation in Victoria, local officials had a good working relationship with their interstate counterparts.

"Any new case in the community is a concern to us. We've got to do everything we can to keep ourselves protected," the premier said.

But Mr Marshall said there was no suggestion yet of closing the border with Victoria.

Also on Monday, SA announced plans to expand the availability of the coronavirus vaccine to anyone over the age of 16 and living in regional SA communities, and a program to provide vaccines on Kangaroo Island.

The Royal Flying Doctor Service will deliver 3500 vaccines to the island from early June.
The program comes after a team was sent there in May to vaccinate priority groups, including frontline healthcare workers, aged care residents and emergency workers.

The federal MP for the Island, Rebekha Sharkie, said she first raised the issue of access for KI residents in January. She is pleased the state government had found a solution, working with the council to open the Kingscote Town Hall as a vaccine hub.

"I appreciate that rolling out COVID-19 vaccinations across the state is a complex and challenging logistical exercise," she said.

"But it shouldn't take five months to set up a vaccine roll-out for a community that has limited options for accessing this important health program."

SA reported just one new virus case on Monday in a returned traveller although the man's case is believed to be an old infection.

There is just one active infection in the state, also a returned traveller in hotel quarantine.