Health officials still need to know whether the women who travelled in Northland were infectious while they were there, Director-General of health Dr Ashley Bloomfield says.
Police last night found the second woman in West Auckland after a three-day search.
Bloomfield said the woman was symptomatic and was not co-operating with officials on locations of interest.
"The person I understand was being tested last night ... we should have the result through this morning," Bloomfield said.
The pair crossed the Auckland border on 2 October and spent three days in Te Tai Tokerau.
The second woman was taken into custody under section 70 of the Health Act, Police said they would continue to investigate and "will be following up with this individual".
The first woman, who tested positive for Covid-19 in Whangārei, had also refused to reveal where she travelled and who she came into contact with. Both are now in MIQ.
Northland was moved to alert level 3 on Friday and will stay in level 3 until 11.59pm on Thursday, Prime Minister Jacinda Ardern announced yesterday.
Bloomfield said police believed the first woman spent two to three days in Northland, based on transactions and phone records.
"What we really want to know is more detail about the places and the times they were in those places.
"The big question is, were they infectious out in the community in Northland, and that's why we need to know where they are and get on and test people who they may have had contact with."
Locations of interest so far are: Kingswood Manor Motel, Whangārei, on 4 October and the Comfort Hotel Flames, Whangārei on 3 October; petrol stations BP Connect Wylies Woodhill for 2 and 3 October and Z Kensington Whangārei on 4 October; and Pepe's Dairy Onerahi on 3 October.
No traces of Covid-19 have been found in wastewater testing in Northland, he said.
In the Waikato, where parts of the region are in level 3, Bloomfield said "things are looking promising".
"In part, what gives us confidence is high levels of testing and we want to see those continue over the next few days."
There had been a good response from the education and health sectors to the vaccine order announced yesterday, he said.
"Mandatory vaccination is not something you do lightly. It's quite an extraordinary measure. These are extraordinary times."
Whether the mandates might be extended to other sectors remains under review. "But at the moment, those are two hugely important workforces and it's great to see the wide support for those announcements.
It was a legal matter whether private businesses could require staff or people visiting the business to be vaccinated, rather than for the Ministry of Health.
"In many respects [private] businesses have a legal basis for doing that ... under health and safety legislation.
"Government will be providing advice and support around that and there is ongoing work about ensuring the legal basis for that is clear."
Bloomfield said vaccine mandates were likely to widen.
"There is already a precedent, both here you can see and in other countries - it's very widespread in Australia - so I think businesses will start to make their own decisions about this."
Heath and epidemiology experts have been looking at whether New Zealand should allow Covid-19 to become endemic, arguing the increased deaths, hospitalisations would leave long term costs to health and the economy.
Bloomfield said New Zealand should continue to to deal with the virus on its own terms.
"Virtually every other country, this virus has become endemic, and people often talk about living with the virus.
"Well, we've been living with the virus for the last twenty months.
"But, as Michael Baker said very nicely I think, we've been living with it on our own terms and we want to continue doing that.
"Our terms are an incredibly high vaccination rate and continuing to aggressively go after infections when they are out there in the community which is what we're continuing to do."