The Hawke's Bay Regional Investment Company is set to gain twice the amount of Smedley Station land than has been reported if the Ruataniwha scheme goes ahead.
Howard Estate Advisory Board chairman Pat Portas raised the 350ha that were on the table this week.
"There is quite a large area that is in question here not only the bit of land that is being swapped," he said.
Mr Portas spoke after the first board meeting following the land swap deal between the HBRIC and the Department of Conservation (DoC) going through this week.
Under the deal DoC will exchange 17ha of its land for 117ha of land the HBRIC will potentially buy from Smedley Station.
Mr Portas said the land from the 5000ha station the HBRIC would receive from the deal was "serious bush".
"What we are also losing there is some good grazing land, but hey that is not the area that is being swapped [with DoC]."
HBRIC chief executive Andrew Newman said while some of the land would be used in the land swap with DoC, the remainder would be retained by the investment company.
Of the remaining 180ha he said some would be inundated by the reservoir and the other part would form part of the overall offset mitigation package developed as part of the dam project that went through a board of inquiry earlier.
"There is an offset mitigation package and that land will be retired from farming and revert back to native land," Mr Newman said.
"That land will be returned from farming."
In the lead-up to the deal, which still depends on the scheme progressing, Mr Portas said Smedley Station entered a negotiation process with the HBRIC "months ago".
"We have come to an amicable agreement and what HBRIC have decided to do with that land is totally up to them," he said.
When asked about the 350ha he said that would be a part of the station's land that would be inaccessible if the Ruataniwha Dam happened.
"There will a huge body of water which is going to stop us getting from one part of our farm to another," he said.
In clarifying the land on the table, Mr Portas said Smedley Station was Crown land in the truest sense of the term - it was owned by the monarch not the state, the New Zealand Government.
"Smedley in 1919 was gifted to the king of the day, King George. It was gifted for the education of young people in agriculture by Josiah Howard," he said.
While the monarch owned the land somebody in New Zealand had to care for it. That was where the Public Trust and the Howard Estate Advisory Board came in.
"The trustees are looking after it on behalf of the Crown," he said. "The trustees being the public trust and the Howard Estate Advisory Board who advise the Public Trust on matters about the farm."