Hawke's Bay farmers are still right behind the concept of the Ruataniwha water storage scheme.
But a regional farmer representative says those in the Tukituki River catchment who will be using it, still need to be convinced about the economics of the $600 million project.
There's intensive debate over the possible environment impacts, including the Regional Council's proposed district plan change to allow increased nitrate levels from intensive farming.
Federated Farmers Hawke's Bay president, Will Foley, says with the knowledge available now, farmers can manage the environmental effects of more intensive agriculture.
But he says one of the main concerns for farmers remains the cost for those using the scheme.
Mr Foley says the dam cost will be confirmed when the construction contract is announced in about a month.
But he says farmers are also anxious about the proposed district plan changes covering issues such as nutrient and stock management, which are likely to go ahead irrespective of the dam decision and will impact on all farmers, regardless of whether they are irrigation users.