TrustPower's withdrawal from the Ruataniwha dam project has unnerved the other major potential investor, Ngai Tahu, because the electricity company knows the business, Hawke's Bay iwi Ngati Kahungunu says.
TrustPower has walked away from the investment because it says it's too risky and it isn't happy with the return it might receive.
The Hawke's Bay Regional Council is looking for alternative investors in the water storage scheme following TrustPower's withdrawal.
Ngati Kahungunu Runanga chair Ngahiwi Tomoana said he had spoken to Ngai Tahu chairman Sir Mark Solomon about the issue.
Sir Mark had told him the South Island tribe was nervous because TrustPower knew the business and Ngai Tahu did not.
Ngai Tahu was seeking answers about its involvement, which included the commercial criteria of the project.