Questions are being raised by Labour over whether the Minister responsible for the Transport Accident Investigation Commission is doing enough to monitor standards.
An RNZ Insight programme has revealed funding shortages and that Commission investigators have had up to three times the workload recommended by the International Civil Aviation Organisation.
They have been also breached international timing guidelines on completing air accident reports.
Listen to part two of Investigating our Air Investigations Part 2:
Listen to part one here.
Labour's Transport spokesperson Sue Moroney said the Prime Minister needed to get involved and if Craig Foss wasn't up to the job he needed to be replaced with a Minister who was prepared to maintain standards and hold the Commission to account.
Insight has seen documents under the Official Information Act in which the Commission is described by the Ministry of Transport, in a request for more funding, as being increasingly divergent from Government, international regulator and public expectations.
Additional funding of $1.3 million was approved last year but air accident reports into helicopter crashes that took place in 2013 and 2014 have still not been published.
The International Civil Aviation Organisation, or ICAO, requires accident reports to be produced in one year if possible with an interim report to be produced if the publication date drifts too far beyond 12 months. TAIC has not produced an interim report for either of the helicopter accidents.
The 2014 helicopter crash near the summit of Mount Alta killed Auckland construction boss Jerome Box, but four of his friends on board the helicopter survived. His widow, Adelle Box, was looking for answers but was not satisfied with TAIC's conduct of the investigation or the time it was taking.
Associate Transport Minister Craig Foss said he believed TAIC was doing a good job and that he had confidence in the Commission. Investigators do a difficult job under difficult conditions and relatives often have their own perspective on how air crash investigations should be run, and what the outcomes should be, he said.
But Labour Transport spokesperson Sue Moroney argued that New Zealand's international reputation and high level of tourism industry revenue was at risk if TAIC didn't do a good job in finding the true cause of air accidents.
Sue Moroney claimed that Associate Transport Minister Craig Foss has failed to act on problems relating to TAIC that have been evident since 2010 and that he has repeatedly failed to act on those problems, which she said was totally unacceptable from the public's point of view.