A man in his 20s and a woman in her 40s are among three people to die with COVID-19 in South Australia, as the state records 4,274 daily cases on the eve of the election.
The third death was a man in his 80s and there are now 21,651 active COVID cases in the state.
South Australia now has 136 people with the virus in hospital, including five in intensive care and three of them on ventilators.
It comes as more than a quarter of eligible South Australians have opted to attend an early voting centre or cast a postal vote.
More than 170,000 pre-poll votes have already been cast and a further 160,000 postal vote applications have been lodged — a huge increase on four years ago.
Electoral Commission SA data shows there have been 172,316 pre-poll votes, including more than 36,000 yesterday alone.
Chief Public Health Officer Professor Nicola Spurrier has estimated that aside from the people isolating with COVID, up to 80,000 close contacts could also be quarantining.
"When we have smaller case numbers, we can easily tell you how many close contacts," she told ABC Radio Adelaide.
Professor Spurrier said the modelling predicted that cases would rise once most restrictions were eased.
"There's really nothing in terms of our public health and social measures other than masks at the moment," she said.
"Now that we have the vaccine, our focus is on hospitalisations and severe disease, and we are watching our hospital cases very closely."
She said the rise in hospital numbers was concerning and urged the remaining 30 per cent of eligible South Australians to get their booster.
"We just have to see how much milage we can get out of the vaccination," she said.
Professor Spurrier said authorities were "holding off" putting restrictions back in place.
When asked if restrictions were eased too quickly and to keep the COVID-fatigued public on side, Professor Spurrier said it was a "complex decision-making process" and could not answer "yes or no".
