South Australia will drop the requirement for COVID-19 close contacts to isolate for seven days, but not for another week.
The change comes into effect from Saturday, April 30 bringing SA in line with NSW, Victoria, Queensland and the ACT.
It will come with new rules including a requirement for close contacts of positive cases to take five rapid antigen tests over the seven-day period.
They will also be required to wear masks when outside the home, are banned from visiting high-risk settings such as aged care centres, and must tell their employers and any schools they have contact with of their status.
Close contacts will further be urged to avoid any non-essential gatherings or contact with vulnerable people.
If they develop symptoms they must take a PCR test and isolate until receiving the result.
"It's a very big change, an important step," Chief Public Health Officer Nicola Spurrier said on Friday.
"But we still need to take some precautions, because we know people who are close contacts are at higher risk of catching the disease."
Premier Peter Malinauskas said the change would provide considerable relief to the business sector impacted by the isolation requirements even though it might result in case numbers "slightly ticking up".
"We can do this because our hospital system is managing to cope in difficult circumstances," he said.
"The change to close contact arrangements has been a thoughtful and considered judgement.
"Which is why we're going to buy that additional week to ensure that the case numbers continue to operate at the appropriate levels and our hospital system is coping."
The changes came after a meeting of SA's Emergency Management Council was brought forward from Tuesday next week.
The decision also followed a rise in infections on Friday to 4500, up from 4079 on Thursday and after SA dropped its widespread mask mandates last week.
