South Australia's Omicron peak will fall short of the original prediction of 8000 COVID-19 cases a day.
SA Health modelling released on Tuesday shows the state is now forecast to reach about 5500 daily new cases in the coming weeks.
COVID-19 hospitalisations are also forecast to be lower than expected, the health department said.
"While it is difficult to predict human behaviour, this is a good indication that South Australians are continuing to do the right thing," SA Health said in a statement.
The state recorded 5068 cases and four deaths on Tuesday.
There are 206 COVID-19 patients in hospital, with 11 in intensive care and one on a ventilator.
It comes as SA Premier Peter Malinauskas announced vaccination clinics would remain open across the state, despite plans to close eight sites this week.
"Only in recent days was my government advised there were vaccination clinics set to close in the coming weeks," Mr Malinauskas told reporters on Tuesday.
He spoke to the media following an urgent emergency management council meeting held on Thursday due to a spike in COVID-19 hospitalisations.
"Two hundred hospitalisations is a big number ... we are under no illusion the size of the challenge being imposed on our hospital system is extraordinary," the premier said.
He said hundreds of thousands of South Australians were still eligible for a third dose of the vaccine and yet to receive it, with 200,000 others eligible for their fourth dose.
Mr Malinauskas reminded the community that without being vaccinated the risk of hospitalisation increases.
"We don't want to go back to a situation where South Australians have to go back to tougher restrictions," he said.
The government will also roll out a $2 million campaign to encourage vaccinations.
WHICH CLINICS WILL STAY OPEN:
* Wayville was set to close on May 31, but will now close on July 31
* Playford and Noarlunga were set to close on May 29, but will stay open until June 30
* Regional clinics will stay open until June 30
* Pop-up clinics will stay open until some time in June.
