PEOPLE travelling to South Australia no longer have to undergo three tests after the government changed testing requirements.

Previous to the changes which occurred Wednesday, travellers from New South Wales, Victoria and ACT needed to have a test 72 hours before arrival, upon arrival and again on day six.

Now, asymptomatic travellers from these states only need to test prior to arrival.

South Australian Premier Steven Marshall said these changes had come after concerns the SA health system had become inundated with asymptomatic people getting tested.

"We have received advice from SA Pathology and SA Health that it is now appropriate to focus our testing efforts on South Australians with symptoms, close contacts and any other people directed by SA Health, rather than asymptomatic interstate arrivals who have recently returned a negative result," he said.

"This will free-up resources which can be concentrated on South Australians getting tested.

"Interstate arrivals with symptoms must still get tested immediately upon arrival into South Australia."