The change comes amid growing confidence the worrying Parafield cluster of COVID-19 infections has been brought under control with no new cases reported on Friday for the sixth day in a row.

Venues are now allowed one person to every two square metres, effectively doubling the number of people to be served at any one time.

The change was quickly endorsed by Business SA, which said many venues would be "breathing a sigh of relief".

"Today's decision recognises the importance of the economic needs of South Australia, which must be balanced with the ongoing health advice for COVID-19," chief executive Martin Haese said.

"The density rule change will not be a silver bullet for every business owner who is at breaking point after the most difficult year of their lives, but it will help."

SA Police Commissioner Grant Stevens said the decision was made by the state's transition committee despite Chief Public Health Officer Nicola Spurrier proposing to wait until next week.

"Given the economic implications, the impact on employment, the current time of the year, our current performance ... we endorse a one person per two square metre rule for hospitality," he said.

All other restrictions will remain in place, with a further assessment next week.

Professor Spurrier said given the current circumstances in respect to the Parafield cluster it was somewhat difficult to make totally accurate determinations on the level of risk in the wider community.

She confirmed her recommendation was to keep the wider density requirement ahead of a review next week.

"There are a lot of unknowns," she said.

"The longer we go through this and the more days we go with no cases in our community, obviously we can all feel more confident.

"But I am providing the best advice that I can."

With almost a week of new cases, the Parafield cluster remains at 33 with only seven considered active.

About 275 people are still in quarantine after that figure peaked around 6000 at the height of the outbreak.

Mr Stevens said the take-up of QR codes this week, equating to about 1.1 million check-ins across the state, was a "game-changer" in terms of contact tracing.

"(This) has given us some confidence to manage the risk around this current response to the Parafield cluster," he said.

He said he was hopeful the state could further ease restrictions on December 14 as planned.

SA last lifted coronavirus measures on Tuesday, when it also dropped all border restrictions with Victoria.

It is now open to travellers from all states and territories as well as those from New Zealand.

Australian Associated Press