The people flew to New Zealand through Sydney and were caught at the border, Dr Ashley Bloomfield says.
Three people have travelled to New Zealand from Melbourne in breach of the lockdown in the Australian state of Victoria, health officials have announced.
Director-General of Health Dr Ashley Bloomfield revealed the breach at a press conference on Wednesday.
The trio left Melbourne and flew to New Zealand through Sydney last week, he said.
They were identified upon arrival in New Zealand and tested negative for Covid-19.
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Bloomfield said they have been transferred to managed isolation facilities, and their day three test results are due back on Wednesday.
A flight board at the Virgin domestic departures terminal of Melbourne Airport displays a number of cancelled flights after a lockdown was announced.
Quarantine-free travel between Victoria and New Zealand has been on hold since May 25, following a community Covid-19 outbreak in the Australian state.
This is set to continue until at least 11.59pm on Thursday, but there are exemptions for New Zealand residents flying home, the first of whom will arrive in Auckland on Wednesday.
The Ministry of Health also announced there are two new cases of Covid-19 in managed isolation.
There are no new cases in the community.
The new cases came on flights from India via Qatar and from Bahrain via the United Arab Emirates.
Two historical cases have also been reported. Both came on flights from India via Qatar, and are not considered infectious.
A community testing station in Waitara, Taranaki. (File photo)
The announcement comes after a Covid-19 patient was transferred to Middlemore Hospital on Wednesday.
A Counties Manukau District Health Board spokeswoman said the patient was transferred from the Jet Park quarantine facility overnight.
The patient had pneumonia, secondary to their Covid-19, she said.
The number of travellers who came from Melbourne to New Zealand between May 20-25, before the lockdown was announced, is now 5160.
Of those, 3184 have returned a negative test result.
A further 1774 require no action as they have returned to Australia or have reached the 14-day post exposure date.
Included in the 1774 are 200 travellers who have not been tested despite multiple attempts by the Ministry of Health to contact them.
The remaining 202 are exempt from testing because they are under the age of 12.
On Tuesday, New Zealand hit 100 days without community transmission of Covid-19.
The Government has confirmed about a million doses of the Pfizer vaccine will arrive in New Zealand during July.
The Government says the vaccine will arrive in several shipments throughout the second half of the month.
As of Wednesday, the total number of active cases in New Zealand is 24, while the total number of confirmed cases is 2340.