Health officials are working on the assumption, that an Australian who visited Wellington last weekend was infected with the Delta variant.
Confirmation of that is expected this morning.
Testing sites and Healthline struggled to cope with demand yesterday, as people rushed to get a test.
The tourist spent his time in the capital visiting busy locations like Te Papa, a central supermarket, and bars, restaurants and cafes.
Covid-19 Response Minister Chris Hipkins says more testing centres will be opened today, and more people are being rostered on to answer the Heathline phones.
Wellington, Kapiti and Wairarapa will remain at Alert Level Two until Monday.