There are no new cases of Covid-19 in the community today but one case has been detected in managed isolation.
Director general of health Ashley Bloomfield said the genomic sequencing had confirmed the border link with the community case in Melbourne, and two people in New Zealand who had been in locations of interest in Victoria had contacted Healthline.
They had been given health advice, he said.
The Ministry of Health said the case in MIQ arrived from Indonesia, via Singapore, on May 7.
Anyone who was at one of the locations of interest in Melbourne at the specified time cannot travel to New Zealand for 14 days from exposure, the ministry said in a statement.
Those who were already in New Zealand must call Healthline for advice surrounding isolating and testing.
The Ministry of Health was now urgently tracking down 4500 passengers who recently travelled from Victoria to New Zealand to remind them of safety measures they must take.
Five previously reported cases had recovered, bringing the total number of active cases in New Zealand to 18.
A previously reported historical case has now been reclassified as "not a case" and has now been removed from our tally, the ministry said.
It comes as no cases of the deadly virus were reported in the community yesterday, in the Ministry of Health's latest update.
One new confirmed positive case was reported in managed isolation yesterday - a traveller from Thailand who arrived last Friday, May 7.
The returnee flew here via Singapore and touched down in Auckland, where they are carrying out their 14-day managed isolation and quarantine period.
They tested positive on day 3 testing.
As of yesterday, the seven-day rolling average of new cases found at New Zealand's border stands at two.
Two people who previously had the virus have now recovered, the Ministry of Health said.
The total number of active cases in the country is 22. Our total number of confirmed cases now stands at 2287.
Since the start of the year, there have been 59 historical cases of Covid identified - out of a total of 471 cases.
"A previously reported historical case has now been reclassified as a 'not a case' and has now been removed from our tally," the statement said.
Today's update comes as the Ministry of Health's current assessment of the public health risk to New Zealand remains low - after a confirmed Covid case was identified in the community in Melbourne a few days ago.
"At this stage the ministry is recommending that quarantine-free travel between New Zealand the state of Victoria can continue with certain additional precautions in place. "