Today is meant to bring with it the deadline for farmers to sign up to the Ruataniwha Dam scheme.

The Hawke's Bay Regional Investment Company is supposed to decide if it's financially viable to go ahead with the $275 million scheme.

Regional Council chair Fenton Wilson said the High Court action between Forest and Bird and the Department of Conservation over a land swap needed for the project, is making farmers apprehensive.

"Today still remains the day for farmers to make their minds up. Are they in or are they out?"

"The 11th was always the day for the farming community to get their decisions made."

Mr Wilson said they still want farmers to commit - as, at last count, they only had 49% of the total number needed to make the scheme financially viable.

"There is still a matter of urgency for farmers to sign up for water, and that hasn't stopped."