The price the New Zealand Defence Force pays to provide the likes of humanitarian relief, strategic airlift and VIP transport is continuing to balloon.

Documents obtained by Newshub show since 2016, $97.7 million has been spent on maintenance and repair costs for the C-130 Hercules and Boeing 757 fleets.

The Defence Force says a decline in Boeing 757 expenditure in 2018/19 is "the result of the comparatively low cost of an engine overhaul and a change in maintenance scheduling".

Defence Minister Ron Mark admits it's frustrating and pointed the finger at the former National Government.

"There was plenty of opportunity to take positive steps forward for their replacement. If they'd been ordered back then, we'd be receiving them now. That didn't happen and just like many other Governments before, these cans were kicked down the road, decisions not made and we are where we are".

Five Hercules C-130 aircraft are available to the Defence Force and have been since 1965. They provide strategic airlift and tactical airlift as well as participating in international training exercises. Chief of Defence Force Kevin Short told Newshub earlier in 2019 they struggle to have two available at any one time.

In June, the entire fleet was grounded.

A Defence Force spokesperson told Newshub currently two Hercules aircraft are serviceable. Of the other three, one is undergoing fuel tank repair, one is undergoing structural repair and one is on 35-day servicing.

The Government plans to replace the archaic aircraft with new C-130J-30 Super Hercules in 2023. It was picked as the high priority project within the Government's 2019 defence spending plan. 

Mark says it's a perfect replacement and a decision will be made before the 2020 election.

 

"We're getting a final price so I can put a Cabinet paper together and take it to Cabinet for the 2020 Budget and then we'll get a decision and announce that. Make no mistake, this Government will make that decision" he said. 

"We're not going to let this bow wave of delayed decision making to continue."

National Party defence spokesperson Mark Mitchell told Newshub a contingency plan around the current fleet should be looked into.

"What I'd like to see is, through the ministry, we look at a leasing option or something like that being put in place, if we need an interim measure before those Super Hercules are brought online."

He says despite the flailing fleet, reputational damage isn't a problem.

"If you actually had a look at our operational deployments, we operate in terms of availability at a much higher level than most of coalition partners because our people are so good at maintaining and keeping our equipment going".

The two 757s carry personnel and equipment, but also provide VIP transport. There have been a number of high profile problems since the acquisitions in 2003. Currently one Boeing 757 is available. The other is on a scheduled servicing.

A week of breakdowns involving Prime Minister Jacinda Ardern in July made clear the aircraft are reaching the end of their lifespan.

In June, a second plane had to be sent to pick up Deputy Prime Minister Winston Peters when one of them broke down in Vanuatu.

In 2016, former Prime Minister John Key had to be rescued when a 757 broke down twice, stranding him and a delegation of nearly 100 in Townsville, Australia en route to India.

Despite their VIP transport capability, the Defence Minister says they aren't fit for military purposes.

 

"People made the decision to buy a commercial airliner for use as a strategic airlift platform for the Defence Force but it's the wrong aircraft," Mark told Newshub.

The Defence Capability Plan forecasts the two aircraft be replaced post 2028.

"Hopefully that decision will be more around an aircraft that is fit for military purposes. Is able to handle the conditions expected in Antarctica in that time given climate change. And an aircraft that will be versatile enough to fulfil the VIP role."

But Mark also thought the idea of splitting up the roles of the 757 - one for VIP transport, one for strategic airlift - could be looked at in the future.

Australia has acquired four jets, modified Gulfstream G550 aircraft, to "strengthen electronic warfare support to naval, air and land forces for operations in complex electromagnetic environments".

Mark says a Gulfstream aircraft for VIP purposes could be a sensible consideration - but it's a decision that is for the Government of the day.

"I'm also conscious that in order to maintain capability we need social licence. There is a widely held view amongst New Zealanders where they become sceptical of what they might consider extravagant expenditure and I fully get that."

Mitchell was the previous Minister of Defence and says he wanted to pursue dual use aircraft. 

"Get rid of the 757s, and have one platform that could perform all of the functions and perhaps have a taylor made pod that can be inserted into the aircraft to converts its use into VIP transport or troop transport or cargo."

"I wouldn't like to see a dedicated aircraft for VIP travel. I think we're a small Defence Force and we have to be able to have multiple capability with whatever we're purchasing," he said.