MP David Seymour is shocked that only half of COVID-19 case contacts have returned test results, meaning there could still be undetected coronavirus in the community.
The ACT leader asked officials during a virtual meeting of Parliament's Health Select Committee how many of the 15,741 current known contacts of COVID-19 cases have returned a test, positive or negative.
Director of Public Health Dr Caroline McElnay revealed that, of the 369 close-plus contacts, who are considered the highest risk, only 51 percent had returned a test, of which 11 percent came back positive.
Of the 14,967 close contacts, which is the largest group, 56 percent have results back, and 0.2 percent have been positive. And of the 405 casual-plus contacts, considered the lowest risk, 58 percent have a result back, none of which were positive.
"You talk every day about how many tests have been done, but not how many are returned and not how many of them were actually people who had been at locations of interest," Seymour said to COVID-19 Response Minister Chris Hipkins.
"I think this is a very important number."
Hipkins said the Government doesn't expect every COVID-19 case contact to return a test result immediately after they have been identified.
"What I would point out is that people get tested on a cycle and people aren't always tested immediately as soon as they're identified as a potential contact," Hipkins said.
"In some cases they'll wait a day or two because if they've just been potentially a contact, they may not be tested straight away. They'll be entered into the system as a contact straight away, but they may not be tested straight away."
Seymour said after the meeting he was frustrated that the information "had to be painfully extracted like a gnarly wisdom tooth", and questioned why health officials haven't been including it in the daily update.
"Why can't the Ministry of Health simply share its information? The best the minister could say is that they've undertaken to talk about it further."
The Ministry of Health revealed on Tuesday an additional 41 COVID-19 cases of the Delta strain in the community, bringing the total to 148, 11 of which are in Wellington and the rest in Auckland.
All of the cases have or are being transferred safely to a managed isolation facility, under strict infection prevention and control procedures.
An August 15 service at the Assembly of God Church of Samoa remains the event with the highest number of COVID-19 cases in the current outbreak, with 58 cases.
More than 26,500 swabs were taken across Auckland on Monday, while 2533 tests were processed in Wellington, out of a total 35,376 tests processed across New Zealand.