There is one new case of Covid-19 in New Zealand managed isolation, with none in the community.
The Ministry of Health said its officials were in close contact with counterparts in Victoria following the state's seven-day lockdown announced today.
It was "crucial" that any Kiwi travellers in Victoria since May 11 were checking Victoria Health's locations of interest.
There were 34 positive cases in Melbourne as at 1pm today with 150 exposure sites across the city.
Director general of health Dr Ashley Bloomfield said it was "critically important" people record their movements and scanned QR codes in the event that positive cases were found in New Zealand.
Anyone who had been at a location of interest at the specified time must immediately self-isolate and call Healthline on 0800 358 5453.
Anyone with symptoms who had been in the wider Melbourne area since May 11 should also ring Healthline and arrange a test. People who had been in the Whittlesea local government area since May 11 should also ring Healthline.
Melbourne has just been placed in a 7-day lockdown, described as a "circuit-breaker" after the latest cluster continued to grow.
Health officials on this side of the Tasman are now expected to extend the pause with the NZ-Victoria travel bubble, which was initially suspended for 72 hours on Tuesday.
Covid-19 Response Minister Chris Hipkins said at the time that that pause would be under constant review.
New Zealand continues to record no cases of Covid-19 in the community.
Yesterday, no positive cases were detected at the border either - with the Ministry of Health reporting no new cases at any of the managed isolation facilities around the country.
The seven-day rolling average of new cases detected at the border is two.
The total number of active cases in the country, as of yesterday, stood at 22. The total number of confirmed cases stands at 2313.
Since January 1, there have been 64 historical cases recorded out of a total of 497 cases.
If you have been in Melbourne
Authorities in Melbourne and wider Victoria announced a seven-day lockdown this afternoon after the state's cluster grew to 26 cases.
Acting Victoria Premier James Merlino said the lockdown would last from midnight until Friday morning next week, with only five reasons to leave the house.
Those five reasons include to get food and supplies, authorised work, care and caregiving for medical reasons, exercise for up to two hours each day with one other person, and getting vaccinated.
It is the fourth time Melbourne has been placed in a lockdown.
Because the first case in the Melbourne cluster was identified just over two weeks ago - on May 11 - it is possible that people from the Whittlesea local government area in Melbourne may have been exposed to the virus and are now in New Zealand, the Ministry of Health said.
"The ministry is asking anyone who has been in that area to have a test five days after they were last in Whittlesea and stay in their accommodation until they have a negative test result - even if they do no have symptoms."
Anyone from the wider Melbourne region who develops symptoms while in New Zealand is also urged to take action immediately by calling Healthline on 0800 358 5453 and arrange to get a Covid test.
The locations of interest connected to the Melbourne cluster are regularly updated on Victoria's dedicated Covid website.