The New South Wales health authority has issued an alert about two flights between Wellington and Sydney linked to a Sydney Covid-19 case.

New South Wales Health issued the alert late on Tuesday night.

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 were Qantas QF163, which left Sydney at 7.05pm on Friday 18 June and landed in Wellington at 12.12am on Saturday; and Air New Zealand NZ247, which left Wellington at 10.13am on Monday 21 June, arriving 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 temporary suspension of quarantine-free travel from New South Wales to New Zealand is now in place, and will last at least 72 hours.

The Australian state yesterday recorded 10 new cases of Covid-19, and new exposure sites there have been announced.

Check latest locations of interest in Sydney on the NSW Health site.

NSW Health did not provide a list of possible exposure sites in Wellington, or any other New Zealand centres.

New Zealand's Ministry of Health has so far confirmed the NSW Health alert, but has not published any locations of interest on this side of the Tasman.

It is also advising anyone who travelled on the flights to isolate and seek a Covid-19 test.

The latest surge in cases in the Sydney Bondi cluster led NSW Premier Gladys Berejiklian to extend the state's mask mandate for all indoor public venues to midnight Wednesday 30 June.

Local government areas of Wollongong and Shellharbour, which had compulsory masks for public transport, would be subjected to the same mask rules as Sydney.

The Westfield Bondi Junction shopping centre continued to be the main area of concern to health authorities on Tuesday.

New Zealand health authorities have urged travellers from the state who have been to a location of interest at the times listed to call Healthline, and isolate themselves until they can be tested for Covid-19 and then return a negative result.

Air New Zealand said the pause on quarantine free travel from Sydney meant 28 flights were cancelled over the next 72 hours.