Deputy Prime Minister Winston Peters is calling for someone to be held accountable over lack of COVID-19 testing at the border but stopped short of saying who that person should be.

Last week, Newshub's Michael Morrah revealed 63.5 percent of border workers hadn't been tested for coronavirus, dispute assurances this was taking place.

Peters told reporters on Tuesday he was "plain alarmed" by those numbers.

"When you find out that something that was promised to be done has not been done, then it's got to be like [a] business, like every other profession I know, a thing called accountability.

"In the end, the person at the top who's been given the responsibility has to be the person that answers."

It's now compulsory for managed isolation staff to get a test. Peters said the border "always has been, in my party's view, our number one priority.

"From the word go we were concerned - my party was concerned - from before we even went into the lockdown that the issue of border security and the quality of surveillance would require the military to be involved from the word go.

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"We thank that the border security should have been the most critical issue where we were assured at all points - which I know we aren't now - that we've done whatever we could to make sure the border was secure.

"When you have given an assurance to Ministers and the public that this [testing] is going on - when we find out those things are not going on - then you've got to ask, 'what on earth is happening'?"

National leader Judith Collins said communications between the Government and Ministry of Health should be released by Prime Minister Jacinda Ardern.

Ardern said the testing didn't meet the Government's expectations.

"What we are learning is while we did have testing stations at the border - we weren't picking up necessarily all asymptomatic workers as we expected," she told The AM Show.

"We have now gone back through and all that [testing] is happening now and we have set out our expectations in an order to make sure that does happen."