Some people tested for COVID-19 during last week's community scare had to be re-swabbed due to a possible "data entry error", the Director-General of Health says.
There was a testing blitz in Auckland and Northland last week after three community COVID-19 cases - all linked to Auckland's Pullman Hotel.
Ashley Bloomfield says three test results couldn't be found in the Ministry of Health systems.
"That could have been because there was a data entry error or sometimes the label simply comes off a sample," Dr Bloomfield told The AM Show.
"It does happen - in the northern region there's been 800,000 tests processed since we started testing there. I think there were three associated with the cases last week when they were doing many thousands of tests.
"They were identified, the people remained isolated and they were rapidly re-tested, and they got their results back as negative.
"Sometimes ... there is a lapse in the testing."
Two people who completed their managed isolation in Auckland's Pullman Hotel last week tested positive for COVID-19 in the community, just days after a Northlander in the same hotel returned a positive test after leaving the facility.
Pullman Hotel staff are now being tested more frequently - twice a week - and those leaving must isolate at home and get a test on day five.
Vaccine brings light at the end of the tunnel - Dr Bloomfield
Dr Bloomfield is confident everyday New Zealanders will have the option to line up for a COVID-19 vaccine in the second half of the year.
Dr Bloomfield told The AM Show he hopes everyone takes up the opportunity to get the jab when the time comes.
"We're aiming to have had every Kiwi offered the vaccine ... to be vaccinated before the end of this calendar year."