The South Australian Opposition Leader has escaped a coronavirus scare, but officials are still expected to shut down a sitting of the state’s parliament.

Thursday’s sitting of both houses is likely to be adjourned after MPs and their staff were advised to limit in-person meetings.

The scare began on Wednesday when former SA Australian Labor premier Jay Weatherill, 57, tested positive for COVID-19 after attending a school reunion in Adelaide on the weekend.

The news prompted Opposition Leader Peter Malinauskas, who had lunch with Mr Weatherill earlier this week, to leave parliament on Wednesday night, get tested and go into self-isolation ahead of the results.

Early on Thursday, Mr Malinauskas tweeted his test had come back negative.

“While I’m relieved by this news, my thoughts are with those Sth Australians who have now got COVID,” he said.

“Now that the virus is in SA, it is more important than ever people get vaccinated.”

Tweet from @PMalinauskasMP

Mr Malinauskas’ deputy Susan Close is also in quarantine after a negative test after being identified as a close contact.

SA Governor Frances Adamson has been forced to do the same.

“Her excellency was tested at about midnight and has returned a negative result,” Government House said in a statement.

“As a close contact, she will nonetheless isolate within Government House for as long as advised by SA Health.”

SA Health reported on Wednesday two men in their 50s had tested positive for the virus after attending the same event as some interstate travellers.

They were the first locally acquired cases of COVID-19 since the state’s borders reopened last week.

“While the cases are currently under investigation, we believe the virus was passed on from an interstate traveller at the event,” SA Health said.

Exposure sites linked to the two cases included a theatre venue in suburban Norwood, a seafood restaurant, a cafe in Adelaide’s CBD and the Business SA headquarters in Unley.

Anyone who attended the event and was unvaccinated is required to quarantine for 14 days.

A child who recently returned from overseas also tested positive for the virus, which took the number of active infections in SA to nine.

There have been 13 cases since the border rules were relaxed on November 23.

Under current arrangements, SA is open to vaccinated travellers from all states and territories, with some requirements for testing and quarantine.

International arrivals are required to quarantine for 14 days, regardless of where they come from.

Local restrictions, such as mandatory mask-wearing on public transport and in most venues, also remain.

The state’s transition committee met on Tuesday but left all travel and local restrictions unchanged despite concerns over the new Omicron variant of the virus.

-with AAP