The company says contracts for a further seven million cubic metres of water a year are currently being reviewed by farmers and their professional advisers.
HBRIC says 48 farms its staff have visited were not interested in signing up to the scheme, in most cases because the property was either close to changing hands or the terrain was not suitable for irrigation.
But in nine cases "the reason for not proceeding is opposition to irrigating altogether or opposition to the RWSS specifically," the report said.
The regional council has agreed to invest up to $80 million in the scheme, provided a number of conditions are met, including that HBRIC secures initial water user agreements for a minimum of 40 million cubic metres a year. The company also needs to finalise a construction contract with the engineering consortium it wants to build the dam, secure funding from corporate investors and central government, and get through a protracted legal battle with environmental groups.
At its meeting on Wednesday, the regional council will be asked to consider a request from HBRIC that the investment company be allowed to borrow up to $4 million to see it through to "financial close" - the date when all the required conditions are met.
A board of inquiry is currently reviewing aspects of a change to an environmental management plan that could affect the viability of the irrigation scheme.
The wording of the plan change has been challenged by Fish & Game, Forest & Bird and the Environment Defence Society.
HBRIC has told the council that with the board of inquiry not expected to finalise its decision until May, and with further appeals possible after that, financial close could be delayed until as late as the end of February next year.