Coronavirus: Deputy Prime Minister Winston Peters claims officials 'covering their butts' over Auckland COVID-19 outbreak

The Deputy Prime Minister has again suggested the Auckland COVID-19 cluster started from a breach at the border despite officials saying there's no evidence this is the case.

When the cluster emerged last month, Winston Peters told Australian media he was told by a "usually very reliable" journalist the city's outbreak was linked to the quarantine system.

He doubled down on those comments in the days that followed.

Officials then and now maintain the source of the Auckland outbreak has yet to be determined. Health Minister Chris Hipkins on Tuesday likened the cluster to a "puzzle" and said a few pieces were still missing.

Asked by Magic Talk's Peter Williams if he still believed the outbreak came from the border despite officials not yet determining the source, Peters said, "They're doing their best to cover their butt".

Genomic sequencing hasn't found a link to positive cases at the border and environmental testing has ruled out the coronavirus came to New Zealand via frozen packaging. 

"We're back now to the most obvious and elementary answer - it happened at our border," Peters said on Tuesday. "It happened because our border security wasn't what it should have been.

"It happened because we didn't put the military in nearly early enough and we're never strict enough."

"When we said we went early and went hard, yes we went early but we didn't go hard the way we should have," he said.

Last month, the Government boosted the number of New Zealand Defence Force (NZDF) personnel at managed isolation and quarantine facilities in the wake of the outbreak.

National leader Judith Collins last week blamed a "systemic failure" by the Government on Auckland's COVID-19 outbreak.

Hipkins said work to identify the source is still ongoing.

"If you can imagine the big cluster and joining all the lines to connect all of the cases - there are still some lines there that we can identify one way but not the other way," he told The AM Show.