As of midnight Sunday, any person who arrives in South Australia from what has been deemed a high community transmission zone (HCTZ) is required to self-quarantine for the remainder of a 14-day period commencing on the last day the person was present in the HCTZ.

They must also undertake a COVID-19 test immediately, another on day five and again on day 12.

HCTZs include the whole of greater Sydney as well as the local government areas of the Central Coast and Wollongong.

Visitors from these areas are also not currently permitted to enter an aged care facility in South Australia.

Anybody who has visited Sydney’s northern beaches will be turned away at the border.

Overseas arrivals who have completed a 14-day quarantine in Sydney, travel directly to the airport and wear a face-mask for the duration of their time at the airport will be granted an exemption.

“We know this is going to significantly affect Christmas travel plans, so we don’t take these decisions lightly,” South Australia Premier Steven Marshall told reporters on Sunday.

“But in this instance we believe that this is the best way that we can protect South Australia from any seeding into our state.”

Chief Health Officer Nicola Spurrier said people from other parts of NSW will still be able to enter SA without going into self-quarantine as long as they have not been in Sydney since December 10.

With 30 more virus cases reported on Sunday, the Sydney outbreak has grown to 70 confirmed infections.

SA recorded just three new cases, all of which were already in hotel quarantine, and is now less than a week away from declaring its recent Parafield cluster officially over.

Authorities consider two incubation cycles, or 28 days, the necessary time frame before an outbreak can be declared eliminated.

-AAP