Taxpayers have coughed up more than one and a half million dollars for the Ruataniwha Dam board of inquiry.

The board's role in the country's largest irrigation scheme has come to a close after months of hearings, submissions and court challenges.

CEO of the Hawke's Bay Regional Council Investment Company, Andrew Newman says the board's costs are fair.

"To get through a major complex process with resource consents for up to 35 years, yeah I'm not unhappy with where we've ended up. I don't think we could have done it more cost effectively with any other process quite frankly."

The figures obtained under the Official Information Act show five board members were paid close to $853,000.

Board chair, former High Court Judge Lester Chisholm was paid $1800 a day in fees.

Other board members were paid up to $800 a day.

A further $90,000 of taxpayers money has been spent on meals, accommodation and travel for the group.

The board's hearings and submissions processes for the project has cost $682,000.

The legal bill for the Board of Inquiry sits at close to $57,000.