Covid-19 Response Minister Chris Hipkins says he won't be putting the 4500 workers in managed isolation facilities under suspicion due to the actions of a border security guard who according to the Prime Minister "was lying" about getting tested for the coronavirus.
The guard is Case B in the most recent cluster, and was last tested six months ago - despite a requirement to be tested fortnightly.
"Border workers don't wear ankle bracelets," Hipkins told RNZ.
"Ultimately, we rely on employers to tell us when people worked and to verify when they have been tested to make sure they are being tested in the appropriate cycle. People go on holiday. People miss shifts. People move into different roles. That sort of thing happens, and only the employers are going to have that detailed information...
"Regardless of how robust you design the system you do need people to act according to the rules ... you actually rely on people doing the right thing and the vast majority of people are doing the right thing ...
"Ultimately we have four and a half thousand people working at our managed isolation facilities. These are people who are working hard, they are honest, they are doing the right thing. I'm not going to put all of them under suspicion because at this point, one person appears to not have been doing the thing they should have been doing."
At the end of the investigation into the situation, decisions would be made about any sanctions that should be applied to the person or their employer, Hipkins said.
But the Government is introducing new rules for testing data regardless.
At a 1pm media briefing on Wednesday, Hipkins announced it would mandatory to report testing data to the National Register from April 27, which would make it easier to gather and check border testing information is up to date and accurate.
That work - "largely for data reporting" - had been underway regardless of the current situation, Hipkins said this morning.
"That was under way anyway. In terms of the risk that this case has identified, it really was this case that identified it. So within the last week it became apparent that it could be a problem and within the last few days it has been verified that it was a problem."
The Government had been "data matching" to identify which MIQ workers had been tested for the coronavirus.
"Of those who have had the data match, more than 90 per cent have been tested within the required timeframe. Of that extra 10 per cent, around 87 per cent of them have been tested a day or two late ... that leaves only a handful of people they have done the data matching for who haven't been tested.
"One of the things they have to work through with the employers is if there is a reason for that - for example, did the person not work their shift or is there some other factor at play here? They are working their way through that. But it would appear from what they have done so far, that the vast majority of people are being tested on time or very close to it."
That "handful of people" equated to about 60 border workers.