NSW health authorities are contacting hundreds of arrivals from New Zealand who may have come into contact with the latest Covid-19 case in Auckland.
NSW Health said it had sent a message to 455 travellers who had arrived from New Zealand since 5 November.
It said the case had acquired the virus in Auckland and those affected passengers were also being called and alerted to several venues in that city the infected person had attended.
The first passengers from New Zealand, under a so-called travel bubble with the country, arrived on 16 October.
In a statement, NSW Health said the risk posed by quarantine-free travel "remains low".
It said passengers on a flight arriving in Sydney from New Zealand on Friday night were provided with the warning.
However, none of the passengers reported having attended those venues and none displayed any symptoms.
NSW Health said airlines in New Zealand would refuse travel to any passengers who had attended these venues.
All arrivals from New Zealand will be asked to monitor for even the mildest of symptoms and get tested and isolate if they appear unwell.
They are also required to remain in isolation until receiving a negative result, in line with routine advice for all people in NSW.
The main venues of concern are:
- A-Z Collection, 61 High Street, Auckland CBD: November 8, from 10:30am to 6:30pm; November 9, from 10.30am to 6:30pm; or November 11, from 10:30am to 6:30pm
- The Vincent Residences, 106 Vincent Street Auckland Central: from 12:00am on November 7 to 12:00pm on 12 November
- Red Pig Restaurant, Auckland CBD: November 7, from 6:00pm to 8.30pm
The warning comes as NSW recorded its sixth day straight of no locally acquired Covid-19 cases.
There was one new case detected, a traveller in hotel quarantine, in the 24 hours to 8pm last night.
During the same period, 18,941 people were tested for the virus.
Under the initial Trans-Tasman travel bubble arrangement, travellers from New Zealand were allowed to enter New South Wales and the Northern Territory.
However, some ended up travelling on to other states, including Victoria, Western Australia, Tasmania and South Australia - none of which had signed up to the arrangement.
It caused confusion among passengers as well as some state leaders, like Daniel Andrews, who believed that travellers were not allowed to leave NSW or the NT.
However that was not the case.