Irrigation New Zealand says it is now or never for the Ruataniwha Dam scheme and is urging Hawke's Bay farmers and growers to back it by Christmas.
Together with Federated Farmers, Irrigation New Zealand will host an interactive meeting to discuss the issue early next month, in a bid to get farmers to back the project.
Chief executive Andrew Curtis said there are concerns rumours and incorrect perceptions are hampering the project's progress.
But he said projects such as the Opua scheme in South Canterbury have proved the benefits of water storage and the same could be true for Hawke's Bay.
Mr Curtis says farmers from North Otago will attend next month's meeting to explain the benefits of water storage, and local dam advocates will also be there.