Defence Minister Gerry Brownlee's being accused by New Zealand First of "spending like a drunken sailor" over the purchase of a new Naval tanker.
Deputy leader Ron Mark claims the new ship is costing the taxpayer twice as much as it should, citing the costs of similar vessels purchased by the Royal Navy and the Norwegian Navy.
Mr Brownlee signed off a cheque in July worth $493m for a new ice-strengthened tanker to replace the Navy's outdated vessel HMNZS Endeavour. He contracted South Korea’s Hyundai Heavy Industries to build the 24,000-tonne ship.
Both the British Navy and the Norwegian Navy tankers are also being built in South Korea, but by a different company, Daewoo Shipbuilding and Marine Engineering (which also bid to get the New Zealand contract, but lost out to Hyundai).
Mr Mark says not only are the Daewoo tankers cheaper, they're either bigger or better or both.
The British Navy will get four 37,000-tonne tankers for a total of NZ$819m, or NZ$204m each. Norway will get one 26,000-tonne tanker costing NZ$218m.
"Why is our Hyundai costing us twice what the Royal Navy is paying for its Daewoos?" questions Mr Mark.
"It is a concern because the $20b that Minister Brownlee signalled in the 2016 Defence White Paper could be blown if he spends like a drunken sailor."
"If the Royal Navy can build four 37,000 tonne tankers in Korea for $204m apiece, why is our 24,000 tonne tanker costing $493m?'
Mr Brownlee's office is yet to provide comment.