SA reopened its border to NSW from midnight Wednesday for the first in months, after the eastern state reached 14 days without reporting any COVID-19 cases with an unknown source, and then a further two days with zero community transmission.

The rule change means anyone entering South Australia from New South Wales from today will not have to quarantine for 14 days.

Chief public health officer Professor Nicola Spurrier said the decision to open up to NSW did carry risk, “but we can’t just wrap ourselves in cotton wool forever”.

As people arrived at Sydney airport to head to Adelaide on Thursday, NSW Premier Gladys Berejiklian praised SA Premier Steven Marshall for having the “courage and the confidence to take that necessary step” of allowing free travel between the states again.

“It’s a big call for his state; I shouldn’t get political but that’s another good Liberal state doing the right thing for the nation,” she told Sydney radio 2GB.

“I heard yesterday that thousands of trips have already been booked – and I’m really pleased by that,” she said.

But yesterday, while acknowledging two days without community transmission, Berejiklian urged caution, with western and south-western Sydney still a concern.

“While there were no locally acquired cases recorded in the past 48 hours, the virus is likely still circulating and it is imperative anyone displaying mild symptoms get tested immediately and not delay their test,” she said.

“Obviously we’d like to see that testing rate continue to be high, and if possible, higher.

Berejiklian also flagged NSW was entering into a higher risk period with school holidays approaching.

“Our population will be more mobile than we have been since about February this year,” she said.

Six new cases were recorded in NSW in the last 24 hours, with all in hotel quarantine.

There are now 74 active cases in the state with three in intensive care, while 55 people have died from the virus.

After SA announced on Tuesday it was reopening its border to NSW, Jetstar advertised flights from Sydney to Adelaide for $59 and Virgin said it would resume daily flights between Sydney and Adelaide from October 2.

Premier Steven Marshall on Tuesday said that while border closures “have been the frontline in our defence here in South Australia: they have served us well, they have enabled us to open up our economy and get tens of thousands of people back to work”, it was time to open up to NSW.

“I am really delighted because I know there have been many, many people inconvenienced by this restriction, but it has been a very important restriction that has kept our state safe,” he said.

-with AAP