There have been no new cases overnight, Director-General of Health Dr Ashley Bloomfield says.
This was despite high levels of testing yesterday in the Wellington region after the Covid-positive Australian tourist's visit to the capital over the weekend.
"So far so good that none of those have come back positive," he told Breakfast.
He said it was "critical" officials continued to see the same pattern today and tomorrow.
Given these dates marked day five and day six from exposure to the man at the locations of interest, Bloomfield said this was when people would start to show signs of infection if they had the virus.
Health authorities were also expecting wastewater testing results from Tuesday and Wednesday back today.
He said this would signal whether there was any Covid-19 in the community and described the testing by ESR as "very sensitive".
Bloomfield admitted the results of whole genome sequencing had not been received from Australia as those who run the lab were sick, but not with Covid-19.
New Zealand health authorities were "acting accordingly" to the virus despite this, he said.
Asked why people were being asked to make appointments to get a test, Bloomfield explained it enabled officials to be "much more certain" they were picking up any Covid-19 infections five days after exposure.
He continued to defend the release of locations of interest from 9am Wednesday, about 10 hours after New South Wales Health advised the public about the case.
Bloomfield said the man was interviewed into the early hours of Wednesday morning, there was a long list of locations and the risk associated with them needed to be addressed.
"Until we know the risk, we don't know what we're asking people to do," he said.
"We're not a sausage factory here.
"We got the list up as quickly as he could."