Ageing Hercules and Orion Air Force planes are proving costly for the Defence Force.
The Defence Force has spent around $360 million on maintenance and repairs over the past 10 years, twice as much as in the previous decade, official figures show.
In 2008, keeping the planes fit for purpose cost about $24m. Two years ago the cost spiked over $50m, and this year the bill is more than $43m.
Defence bought its five Hercules and six Orions in the 1960s and all are coming to the end of their operational lives.
Official documents show the Orions had five engine failures over 15 days last year because of propeller malfunctions.
The Hercules also had propeller leaks and faulty oil gauges.
Replacing the aircraft would be costly and Defence Minister Ron Mark has accused the previous government of putting off the decision.
David Capie from the Centre for Strategic Studies at Victoria University said successive governments had known that the capabilities needed to be replaced and updated.
"But the replacements are all so expensive - an eye watering amount of money - so I think there has been a tendency to think that this is a can that can be kicked down the road," he said.
Documents released under the Official Information Act documents reinforce the risk of keeping the old fleet.
The papers said: "The operation of aircraft that are in excess of 50 years old will result in an increase in unexpected maintenance action. This comes at an increasing cost to support through obsolescence and increased risk to mission success."
National had promised a $20 billion upgrade of the armed forces - but when Mr Mark took charge of the Defence portfolio last year he said there was no hard cash to back that up.
Mr Mark has criticised National for the failure to get new equipment, but National's defence spokesperson Mark Mitchell said the moves were under way to replace the old Orions with with Boeing P8 Poseidon aircraft when his party was in power.
"The fact of the matter is as the minister I already had the process well underway in terms of the procurement on the P8s.
"It's actually this government and this minister that's kicking the can down the road.
"They should have made a decision at least by April or May this year," he said.
He said Mr Mark had put on the brakes by launching a number of reviews.
David Capie said Defence was a portfolio that was highly political and not necessarily a vote winner.
"Most New Zealand political parties probably calculate there's not a lot of votes in the lead-up to elections that can be made in the defence sector but at some point there needs to be some hard decisions made about replacing and investing in these capabilities."
Mr Mark said he would have to make a decision before the end of July whether to replace the Orions with the Boeing P8 Poseidon.
In the meantime, he said officials had reassured him the old planes were safe to fly.
-By Jonathan Mitchell
Wellington City Council has done a U-turn on its recommendation to cut guaranteed funding to support service Citizens Advice Bureau and evict them from three offices to make way for a mobile service, in a unanimous vote this morning.
The Council has decided to give Citizens Advice Bureau $210, 787 in funding for one year, with funding for the second and third year to be decided as part of a review. That's the same amount it has received annually for the last three years.
Two weeks ago, the Grants subcommittee recommended the information and advice service receive a $103,500 one-off grant with no guaranteed funding after that, as well as asking CAB to become a mobile service. It was recommended that CAB be evicted from three council spaces including the most popular CAB Wellington central library office.
The organisation's trained volunteers give people advice and information in a range of areas such as tenancy, employment, immigration and budgeting. It also offer Justice of the Peace services.
Councillor Brian Dawson previously said the council was concerned the service wasn't reaching people in Wellington's most vulnerable suburbs, and questioned whether other organisations were already providing the same services as CAB.
Citizens Advice Bureau's national chief executive Kerry Dalton had argued the six month time period to find a sustainable future for the organisation was not enough time and there hadn't been clear communication with the council over its plans. Ms Dalton had said need for the service has only increased and there was no evidence it was not working effectively.
A petition with thousands of signatures voting against the proposal was handed over via email at a full council meeting today.
Wellington Citizens Advice Bureau area manager Lucy Trevelyan said the decision voted on today was not a win for the organisation, but would allow it to keep helping those in the community and work on a plan to continue getting funding through making changes to the organisation.
"When the future of your organisation relies on grants in order to provide services to the community, it's important to have as much certainty as possible," she said in a statement.
"The new plan will give us the space to consider how CAB can continue to best deliver for the needs of Wellingtonians going forward."
Of the outcome, Councillor Brian Dawson said a review of the service by council and CAB was in everyone's best interests.
"We will need to identify any gaps in existing services and explore ways to fill these gaps," he said in a statement.
"We want to try and make sure youth, refugees, social housing tenants and those in areas of need such as Strathmore and Linden will be covered by services."
Councillor Chris Calvi-Freeman questioned whether the organisation had approached the Government for increased funding.
Chief executive Kerry Dalton said central government provides funding for its national organisation, the majority of which is for its internet service and training.
Dr Ramona Tiatia from the University of Otago Wellington's Public Health Department also presented a petition to council today and said she was glad the fire's putting the CAB under attack "are starting to recede".
Ms Tiatia said the service was an important link for Pasifika and new migrants, who otherwise would have to use mainstream services which often aren't useful.
She said 14,000 Pasifika people use the service annually, of which 80 per cent were walk-in enquiries.
The review of the Wellington Citizens Advice Bureau service will be presented to Council early next year.
Citizens Advice Bureau has faced funding cuts to a number of offices around the country in recent years.