An Australian traveller from Sydney, who visited New Zealand over the weekend has tested positive for Covid-19 upon their return to Australia.

The traveller has been in Wellington from Saturday, June 19 until Monday, June 21.

The Ministry of Health says it is most likely they contracted the virus in Sydney prior to their visit to New Zealand.

The New South Wales health authority issued an alert late on Tuesday about two flights between Wellington and Sydney linked to the case.

It said passengers who were on one flight into Wellington, and one flight back to Sydney last weekend, are considered close contacts of a Covid-19 case.

The flights are Qantas QF163 that departed Sydney at 7.05pm on Friday, June 18 and arrived in Wellington Saturday June 19 12.12am. The other is Air New Zealand NZ247 that departed Wellington Monday, June 21 10.13am and arrived in Sydney at 11:33am.

The Australian state's health authority is urging anyone who was on those flights to get a Covid-19 test, and to self-isolate for 14 days, regardless of the result.

The New Zealand Ministry of Health says four close contacts have been identified so far and are isolating.

'Sites of interest that were visited will be advised as further contact tracing is undertaken. People who have been at these sites will need to isolate and should contact Healthline for further advice.

'Genome sequencing is underway in Australia to see if the case is linked to the current outbreak in Sydney.”

This is the first time an Australian traveller has brought Covid-19 to NZ, and since gone home, says the ministry.

Quarantine free travel between New Zealand and New South wales has been paused for at least 72 hours