Businesses and groups representing Hawke's Bay horticultural interests have voiced concerns about water access to existing growers if the Ruataniwha dam is approved.
Farmer groups, who are generally more supportive of plans to build the dam and its associated water storage scheme for central Hawke's Bay, have also expressed concerns the scheme could be unfair on the area's existing water users.
A diverse range of views from growers and farmers are expressed in submissions lodged with the board of inquiry into the Tukituki Catchment Proposal, set up to consider a combination of a consent application to build the dam and a change to the Hawke's Bay Regional Resource Management Plan, known as Plan Change 6.
In its submission, the Hawke's Bay Fruitgrowers' Association says while the provision of extra security of water supply under the dam proposal is commendable, the project needs to demonstrate sound economics.
"Our concern is that if the new consent applications were granted, there does not appear to be any provision to maintain and enhance food-production operations or to protect the rights of existing consent holders outside of the Irrigation scheme zones," the association says in its submission.
"Granting the consents without such provisions would expose existing downriver consent holders located outside of the irrigation scheme to the will of a profit-driven commercial enterprise to provide water for existing lower-catchment water-take consents.
"We believe there should be an obligation to ensure sufficient quantities of water are available to the lower catchments for food production-related activities and survival water in the case of a drought - this should be a condition attached to any of the new consents if granted."
Heinz Wattie's, which processes about 1200 hectares of crops annually, says all require irrigation at some stage of their growth cycle.
The company is concerned the proposed Plan Change 6 for the Tukituki catchment "will become a precedent for the other catchments in the Heretaunga Plains and that some policies in this proposal which are developed to address specific Tukituki catchment issues will be imposed unnecessarily on other catchments".
Another major produce processor, McCain Foods, says economic constraints mean growers have to produce higher yields, which require effective irrigation systems.
"The proposed changes to the seasonal allocation for existing consent holders will have serious implications on the ability of suppliers being able to fulfil their seasonal obligations of providing adequate yield and quality product to McCain."
Apple orcharding business Mr Apple, which employs up to 1500 people at peak times and pays $30 million in annual wages, says it wants to ensure the plan change and water scheme do not lead to an "inappropriate" reduction in the amount of water it can use, the duration of future consents or that disproportionate additional charges are added to the cost of managing its water permits.
"If the scheme will provide a more reliable source of water for primary producers, then, to that extent, it is generally supported by Mr Apple," the company says.
"However, its cost structure and long-term ownership needs to be transparent and understood. Plan Change 6 seems designed to 'drive' existing water users into the scheme. Essentially, its users will fund the scheme."
Fonterra says it is concerned about the effect the proposal could have on existing dairy farmers in the Tukituki catchment who do not choose to take water from the planned scheme.
"Fonterra is also concerned to ensure that the Tukituki catchment does not become over-allocated, resulting in a situation requiring the 'clawback' of nutrients."
Dairy farmer origination DairyNZ also says it is concerned about the effect of the proposal on existing dairy farmers in the catchment.
"DairyNZ is further concerned to ensure that consent conditions imposed do not unnecessarily increase on-farm costs, administration and management."
Submissions on the proposal are being considered by a board of inquiry which begins hearings in Hastings next week.