Small shareholders Fay Willis and Andrea Chambers said they represented a wider group of people who felt the directors had already chosen which upgrade would be adopted and also felt the upgrade consultation process was ad hoc.
KDIC released a document to shareholders at a meeting in November presenting four options to upgrade the existing water race.
Ms Willis said there was a strong feeling the KDIC directors had already chosen option four, the most expensive one, at a basic cost of $35.3 million, which did not include contingencies.
In a draft letter to be sent to KDIC directors and shareholders, the concerned group acknowledged the existing scheme needed improving, but, they said the directors were proceeding with undue haste which was giving rise to misunderstandings.
''As shareholders, we cannot be expected to approve of any part of any proposed option unless we have a clear understanding of all stages of the development; how it is routed, delivered and financed.''
The letter writers ask that the directors investigate the possibility of a modified option one or option two, at estimated costs of $16,792,548 and $22,922,293, respectively, release more details about the finances of the options shareholders were being asked to consider, and consider a peer review of option four.
''An investment of this magnitude must be peer-reviewed by an independent irrigation/engineering consultancy.''
The letter writers also state many small shareholders are pensioners on fixed incomes.
Mrs Chambers said shareholders were not ready for any vote on the scheme.
''I think it will push shareholders off their land.''
KDIC chairman Geoff Keeling confirmed directors backed option four.
''The directors currently feel it is the most economic option for the scheme in the short-, mid-, long-term future. The shareholders still have the right to say 'no'.''
