South Australia will lift its COVID-19 border restrictions with the ACT from midnight on Tuesday, but quarantine measures for people from NSW will remain for the foreseeable future.
Travellers flying in from Canberra will no longer need to quarantine for 14 days but will not be allowed to arrive by road.
They will still need to seek pre-approval online and will be asked to declare they have not been in NSW or Victoria in the previous 14 days.
Fines will apply to anyone who provides a false declaration.
But SA health officials continue to have concerns over community transmission of the virus in NSW.
They would like to see a two-week period with no community transmission, depending on the source of any new cases.
The last case there of significant concern to SA occurred about three days ago, which would put a decision on the NSW border at least another 10 or 11 days away.
"We're hopeful that the situation with NSW will continue to improve," Police Commissioner Grant Stevens said on Tuesday.
"The indicators are that NSW is heading in the right direction."
But the commissioner said the "level of comfort" South Australian officials had with the situation in the ACT did not yet translate to NSW.
He said SA continued to take into account all health, economic and social issues related to the management of restrictions.
"These measures do come with some consequences, so it's about finding that balance," he said.
SA's latest border changes mean that people can now travel unrestricted from the ACT, the Northern Territory, Tasmania, Queensland and Western Australia.
ACT Chief Minister Andrew Barr said SA's decision was good news and a practical decision to "decouple" the ACT from NSW.
"We've been working patiently and diplomatically behind the scenes to get this decision today," he said.
"On a national level, it's a significant step towards the restarting of domestic aviation in Australia."
Mr Barr said he expected considerable demand for new flights from Canberra to Adelaide.
SA and the ACT reported no new virus cases on Tuesday and both have no active infections.
Australian Associated Press