Defence Minister Ron Mark is one step closer to making the biggest defence procurements in recent years.

Mark will take his proposal to purchase up to four Boeing P-8A Poseidon maritime patrol planes from the United States to the Cabinet Government Administration and Expenditure Review Committee on Tuesday.

The planes, which would replace replace its retiring P-3 maritime patrol fleet, could cost up to US$1.4 billion (NZ$2.03 billion).This would be one of the most significant purchases, since the frigate upgrade.

LAWRENCE SMITH/STUFF Ron Mark's procurement proposal will go to the Cabinet committee on Monday. And while he said he did not want to preempt the final Cabinet decision, he told people to "buckle up".

However, the New Zealand Defence Force says the price is likely to be less than that.

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Once the Cabinet committee had seen the proposal, it would have to go to Cabinet, before a decision on the purchase was made. There was no set date for the proposal to go to cabinet, but Mark said that was expected to happen before the end of July.

During a Foreign Affairs, Defence and Trade Select Committee hearing earlier this month, Mark said he had to start "from scratch" on the procurement plan, when he took on the job as minister, last year.

While the former National government had started the process, Mark said there was nothing to suggest there had been a paper taken to cabinet committee or Cabinet, and he would not endorse a recommendation, without understanding the decision-making process.

"I am confident now that the recommendation I will take to Cabinet committee stacks up, that it is robust, it's justifiable and I'm in the stage where I am consulting with people," he said.

"So my closing comment, not being able to pre-judge what the Cabinet committee or Cabinet might decide, because that is for me to put the case down, I would simply say, put your cellphones in flight mode, put your tray up, buckle in, hold on, it's coming."

In the briefing to the incoming minister, the New Zealand Defence Force (NZDF) and the Ministry of Defence said fleet of six P-3K2 Orions had undertaken military deployments and contributed to stewardship of New Zealand's maritime area of responsibility for the past 60 years.

"The aircraft and their sensors have been upgraded several times but they are now beyond further upgrades."

The Defence White Paper 2016 concluded the Orions needed to be replaced in the mid-2020s.

Meanwhile, official papers release to RNZ found NZDF spent about $360 million on maintenance and repairs of the ageing aircraft over the past 10 years, twice as much as in the previous decade.

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.

Mark said he did not want to be criticised for the decisions he made during his time as minister, especially considering NZDF personnel would have to deal with the equipment for 30 years.

He said he had also reviewed National's Defence White Paper from 2016, and a Defence Policy Statement would be produced early next month.