The Environmental Protection Authority says the Tukituki Catchment Board of Inquiry will continue its work on the Ruataniwha Dam.
Opposition parties say the decision-making process on the proposed Hawke's Bay water storage scheme needs to start from scratch because critical submissions appear to have been suppressed.
Radio New Zealand News revealed last week that the Department of Conservation discarded a highly critical draft submission on the Ruataniwha Dam in favour of a few lines.
It later emerged that the Ministry for Primary Industries had also watered down its criticism.
The Green Party is now suggesting that GNS Science lost a contract with Hawke's Bay Regional Council after it expressed serious concerns about the council's information on the dam.
Greens co-leader Russel Norman says that means the concerns of the Department of Conservation, the Ministry for Primary Industries and GNS Science have all been suppressed.
Dr Norman told Morning Report the scientific information should be on the table so an informed decision can be made.
He says it is hard to see how that can happen, and the process should be started from scratch.
Labour Party conservation spokesperson Ruth Dyson also believes the Government should halt the process and start over.
"It just can't proceed on the basis of so much shonkiness going on, I have never heard of a project that's been so side-tracked and rail-roaded," she says.
Ms Dyson says decisions must be made on the best information available.
Forest and Bird says it is not confident the Government-appointed Board of Inquiry can make an informed decision on whether the dam should proceed.
Inquiry goes on
In a statement, the Environmental Protection Authority says the independent board considering the Ruataniwha Dam is dedicated to fulfilling its duty according to Resource Management Act.
It says the board will thoroughly consider and evaluate all information provided to it through the course of the inquiry and any decision could be appealed to the High Court, although only on points of law.
Conservation Minister Nick Smith says there is no justification for starting the board of inquiry process from scratch.
He says he supports the scientific evidence submitted by the Hawke's Bay Regional Council.
Dr Smith says there has been no political interference in the inquiry and the board of inquiry should be allowed to get on with its job of scrutinising the dam proposal.