There are six new cases of Covid-19 in managed isolation facilities in New Zealand, but no new community cases.

And in further good news, wastewater tests in all four cities that had initially come back as "weak positive" results are now negative.

Four of the six new cases in managed isolation since Friday are people who have travelled from the United States (two people), Malaysia and Saudi Arabia. The other two cases are travellers from India, who came here via Qatar.

Two previously reported cases have now recovered. The total number of active cases in New Zealand today is 27. New Zealand's total number of confirmed cases, since the start of the pandemic in 2020, is 2312.

"A historical case has been identified following a mariner returning a weak positive test result before transferring to their vessel," said the ministry.

"The mariner confirmed they had a positive test result overseas earlier in the year and follow up serology testing has confirmed this. If this has not been reported overseas, it will appear in our figures as a historical case."

Wastewater test results update

Weak positive results were recently detected in Wellington, Christchurch, Rotorua and Queenstown.

Results from further testing in Christchurch, which were outstanding, have now returned negative. The other three cities had all returned negative tests.

"The Ministry's assessment is that these weak positive results were likely from recent positive cases in managed isolation or due to recently recovered cases who are not infectious but continue to shed the virus after returning home or while travelling. There is no risk of infection from Covid-19 in wastewater."