A Hawke's Bay Regional Councillor says council staff have been unable to provide a plan for how the Ruataniwha Dam project will be funded without increasing rates.
The council intends making an $80 million contribution to the $600 million dollar water storage project, but councillor Liz Remmerswaal says the council is not revealing any details about the finances.
To raise $80 million for the proposed dam, the regional council has been selling some of the leases on land it owns.
Liz Remmerswaal says millions of dollars in income has been used to subsidise rates, and she questions whether, once that's gone, rates will need to go up to replace it.
The regional council says the intention is that there will be no direct impact on ratepayers.
It says it expects bigger dividends from its investment company and will also review its costs, but has not provided any detail.