South Australia has dropped its COVID-19 border checks on roads coming into the state and at Adelaide Airport, easing pressure on the state's police resources.

South Australia will scrap its COVID-19 border checkpoints, effective immediately, and will dispense with the need for travellers to check-in online before crossing into SA.

Police Commissioner Grant Stevens says the decision has been taken to ease pressures on police resources and reflects the low levels of coronavirus across Australia.

Under the border arrangements between 350 and 550 police and protective service staff work on the border patrols, including at Adelaide Airport and the road checkpoints, on a daily basis.

They will now return to their usual operational duties with the redeployment to be completed over the next few days.

"We've been monitoring our border activity for at least a couple of weeks based on the absence of COVID-19 in other states," Mr Stevens said on Wednesday.

"We've assessed the risk of someone slipping through the cracks is very low and it's not sustainable to maintain those resources given that level of risk.

"I think it's fair to say that COVID-19 has virtually been eliminated from within the community of Australia.

"Having reached that point, we've made the determination to remove that border checkpoint activity."

Mr Stevens said the decision also reflected increased confidence in the handling of international arrivals in other states.

He said the risk of someone arriving from overseas and finding their way into SA without quarantining was considered very low and there was a national obligation to prevent any virus cases escaping the quarantine program.

But the commissioner said border checks would be reinstated should the level of risk increase.

"We are mindful of the fact we may have to go back into a border checkpoint scenario but let's hope we don't have to," he said.

"Let's hope where we are now in Australia is the position we maintain."

The change came as SA reported no new COVID-19 cases on Wednesday with the state also free of active infections.