Ngāti Kahungunu's submission on the final draft in March said the plan had "fundamental or fatal flaws" because it focused on protecting the economy over the environment.
The building of new dams and topping up rivers and streams with water from the acquifer was "experimental and looks to secure over allocation and water use," Ngāti Kahungunu environment and natural resources director Ngaio Tiuka said.
"It felt like 80 per cent of our discussions were based on the hypothetical impacts on the economy. Council's obligation is looking at the environment and its natural limits and what it can take. But we are just not looking at it that way, we're looking at economics first and that's not a very sustainable model of management."
Tuika, who took part in the working group, said water allocation limits would be scrapped under the plan and replaced with a methodology "that didn't make sense".
"It's giving more leeway to groundwater extraction and that's really really dangerous because if we take out more water than's going in we are starting to mine the acquifer, and you're going to concentrate any contaminants in the water.
"We should be more precautionary. Some of our communities on the outer edges of the acquifer are going to lose water - they already are. Bridge Pa has lost water, Omahu has contaminated borehole water, and some bores around marae have run dry in recent times."
Forest & Bird Hawke's Bay manager Tom Kay said the plan failed to take into account the impact of new schemes, which were being investigated as potential solutions to increase the amount of water.
"There's a whole section in Tank titled 'the benefits of water storage and river augmentation' ...there's no section of all the potential detrimental effects on streams.
"We are kidding ourselves a little bit, we need to acknowledge there are some limits to growth in Hawke's Bay as we've only got so much water we can use. Our economy can't just continue to grow."
In its submission to the plan in March, the Department of Conservation warned new dams could alter rivers and affect wildlife in the region.
Hawke's Bay Regional Council said water storage and river augmentation were only being explored as part of the plan, and were not a given and it did not favour irrigators at all.
"The whole point of setting limits is that there is no more to be taken under the current regime of groundwater extraction or taking from rivers," Hawke's Bay Regional Council senior policy planner Mary-Anne Baker said.
"Both urban and rural areas need to look at improving what they currently use, so once you set a limit it focuses attention on how you efficiently use that limited resource."
The plan did not comply with the Government's proposed National Policy Statement for freshwater in some areas, but could be brought up to speed quickly, she said.
The regional council will next month decide whether to fast track the plan, or take it through the normal, but longer Schedule 1 consultation process.
The streamlined planning process would prevent any appeals through the Environment Court but will need the Environment Minister's approval.
