For the third day running, there were 20 new COVID cases in the community on Monday.
But with record low test numbers, Director-General of Health Dr Ashley Bloomfield says testing must be higher to make sure the outbreak is under control.
"Our most important message today is if you have any symptoms you must get tested, wherever you are in New Zealand."
On Sunday, just 2088 swabs were taken across Auckland, the lowest number since the start of the outbreak.
By 2pm on Monday, just 2000 tests had been taken across the city's 22 testing stations.
The falling test numbers reflect falling locations of interest and fewer people having symptoms due to lockdown, but Dr Bloomfield says getting tested is essential if Auckland is to safely move down a level.
"Our goals are to improve our confidence there is no undetected community transmission in Auckland and to protect the rest of the country from any possible leakage of the virus out of the Auckland region."
To help ramp up testing numbers, there'll be increased testing for health staff caring for COVID patients.
Quarantine workers will be tested twice a week for the next fortnight.
And from Friday, 3000 essential workers crossing the Auckland boundary will need to have proof of weekly testing.
It's the 33 unlinked, mystery COVID cases that are causing the Prime Minister the most concern.
"So long as we don't know where a case has come from we cannot tell if we have other chains of transmission in the community that we haven't isolated yet, that's a cause for concern and it is why testing is so important to us," Jacinda Ardern said on Monday.
And there's a lot riding on it - stamping out Delta so Auckland can move out of lockdown.
