One of the flagship projects in the new Government's regional economic fund, the Opotiki Harbour expansion, has blown out to nearly three times its original estimate.
The harbour expansion would create jobs and provide a boost to local industry, but National is questioning whether it's value for money.
Opotiki Harbour is in one of the most deprived areas of the country, and its development had been budgeted to cost around $50 million.
Now it could be far more expensive.
"Very high numbers like $100 to $150 million. You are talking about 500, 600, maybe even more thousand dollars per job," said Simon Bridges, National's economic development spokesperson.
The expansion would allow larger vessels access to the harbour, opening it up for the aquaculture and marine tourism industries.
It was promoted and supported by National, and now it's the number one project for Regional Economic Development Minister Shane Jones' $1 billion fund.
We can't see anything else that's going to deliver, that's going to stop us paying out benefits.- Opotiki mayor John Forbes
"It's not inexpensive. But I would say for the National Party to attack this project is to sabotage an initiative that they themselves were promoting," Mr Jones said.
The Opotiki mayor, John Forbes, says the cost is more than worth it.
"We can't see anything else that's going to deliver, that's going to stop us paying out benefits. If you want to address deprivation, you do it with opportunity. This is really important for us," he said.
Mr Bridges says National was looking at how to make it cheaper, "to see if we could work it down even in terms of the construction costs, maybe get more revenue for it, maybe see if other parties could come in to make it work".
Mr Jones said he thinks it's "possible to have a more heightened level of acceptance in terms of risk. I think that probity is always the essential test that politicians have to meet. But that shouldn't be used to thwart the ambitions of regions".
Mr Jones says regions like Opotiki desperately need projects like the harbour expansion and that's why he's willing to take a risk. But he'll need sign-off from his Cabinet colleagues, and will take a proposal to them shortly.
Mr Forbes hopes the Government decides to back the plan, despite the cost.