Six new MIQ cases have been reported by the Ministry of Health and no new community cases.
The new cases arrived from India, Malaysia, Saudi Arabia and the USA and are all in Auckland MIQ.
The total number of active cases in NZ is 27.
The ministry said weak positive results were recently detected in Wellington, Christchurch, Rotorua and Queenstown, and further testing in Christchurch has returned negative results.
The ministry's assessment is that the results are most likely from recent positive cases in managed isolation or from 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," the ministry said.