One new community case of COVID-19 has been recorded in the past 24 hours, the Ministry of Health confirmed on Monday.
The person is linked to Auckland's existing cluster and has been in quarantine since Friday.
The latest case, Case H, is a household contact of the four people who tested positive last week, referred to as Cases D, E, F and G respectively.
Cases A, B and C are a south Auckland family who tested positive over the weekend of February 13 and February 14. The daughter, Case A, is a student at Papatoetoe High School and the mother, Case B, is an employee in the laundry department of LSG Sky Chefs, a flight catering facility at Auckland Airport.
The source of the cluster - or how the first case contracted the virus - remains unknown.
Case H, who previously returned a negative test result, has been isolating at home since Monday, February 15, the ministry confirmed. They were transferred to Auckland's quarantine facility, the Jet Park Hotel, on Friday, February 19 as a precautionary measure.
The ministry said the public health risk associated with Case H is considered "very low".
"Due to the steps already taken in identifying, testing and tracing individuals linked to the February cases, as well as Case H isolating at home since Monday and then being in quarantine for the last two days, the public health risk is considered very low," a Ministry of Health spokesperson said in Monday's statement.
As Case H has been in isolation during their infectious period, there are no additional contacts to report.
Six new MIQ cases
Six new imported cases have also been detected in New Zealand's managed isolation facilities, however four are considered historical infections.
Of the 190 cases recorded since January 1, 2021, 33 are now classified as historical.
The two active infections both arrived on February 20. The first travelled via Qatar and tested positive on arrival, however their country of origin is yet to be determined. The second flew from Iraq via the UAE and tested positive on day one of their stay in MIQ. Both are quarantining in Auckland.
The four historical cases are all currently quarantining in Christchurch. The first arrived on December 17 from the United States. It was not reported until Monday as authorities were making sure the case had not been previously recorded in another country.
The second entered the country on February 17 from Morocco via France and Singapore and tested positive on arrival. The third arrived on February 18 from the United States and also tested positive on arrival, as well as the fourth case, who arrived from Colombia via the United States.
Four cases have now recovered, bringing the total number of active cases to 54. New Zealand's total number of confirmed cases now stands at 2001.
The total number of tests processed by laboratories to date is 1,662,321. On Sunday, 3,882 tests were processed. The seven-day rolling average up to yesterday is 10,338 tests.
Contact tracing update
Some casual-plus contacts at Papatoetoe High School - the school attended by one of Auckland's initial cases, Case A - are required to have a second PCR test, the ministry said.
Four teachers and 28 students have been told to undergo a second test due to a record of their result being unavailable or a more recent test being required.
As at 8am on Monday, 31 close contacts and 1,416 casual-plus contacts have been identified at the high school. Following further investigation, an additional three casual-plus contacts have been identified by health officials.
Of the 1416 casual-plus contacts - other students and staff at the school - 1402 have returned negative results. One has tested positive (Case E), and 13 results are pending.
Close contacts of the case are expected to return to school on Wednesday, February 24, or when advised by Auckland Regional Public Health Service (ARPHS).
Contact tracing efforts have identified 125 close contacts associated with all the cases in this cluster - aside from the positive cases which have previously been reported.
As of Monday, three previously-reported close contacts have been ruled out on further investigation, and one infant is not required to be tested.
Of the remainder, 122 close contacts have returned a negative test result. Health officials are awaiting the results for two people - both of whom were at a medical clinic within a similar period to Case C, the father in the original trio. The risk of exposure at this location of interest is considered to be low.
Health officials are continuing to investigate how exactly the first case contracted COVID-19 - however, the source of infection has not yet been identified.
The Auckland Airport precinct where Case B is employed - LSG Sky Chefs - remains the most likely source of the outbreak, but further testing has not identified any potential transmission routes, the ministry said.
The Institute of Environmental Science and Research (ESR) has been reviewing all B.1.1.7 variants - a mutated strain of the coronavirus - identified over the last two months to see if there is a possible link to the new case.
The Four Points by Sheraton managed isolation facility in Auckland, a possibility first acknowledged by health officials last week, continues to be investigated.
"This is where there is a possible genomic similarity between a previous positive case (now recovered) and the current community cases - though we note it is not a direct match," said the statement.
There were 265 returnees at the facility in late December. Thirty-six of these are based overseas. At this stage, 11 out of the 229 based in New Zealand have not been contacted.
"We will continue to follow up with these."
The ministry noted that health officials consider this an "unlikely source" of the infection at this stage, but are pursuing the possibility as part of its ongoing investigations.
MIQ case reported on Sunday
On Sunday, just one new imported case was recorded in managed isolation. That individual, a mariner, is now on-board a commercial vessel at sea, the ministry confirmed.
The mariner tested negative on day one of their stay in managed isolation but subsequently tested positive on day three. The result of this second test was processed after the crew member had already boarded the vessel. Officials are now awaiting the results of genome testing.
"The case had no contact with port workers and given that all policies and procedures were followed, the risk to the community is considered very low," said the spokesperson in Monday's statement.
Mariners are permitted to leave MIQ to board vessels before a test result has been processed to limit the disruption to international shipping.
Health authorities remain in contact with the vessel regarding appropriate quarantine arrangements for all crew on-board.