Five weeks ago, those predictions came true when thousands were struck by a severe gastro bug when Havelock North's water became unsafe.

Iwi chairman Ngahiwi Tomoana says it's a "kick in the guts".

"There's been a general 'she'll be right,' and 'more is better', a flagrant disregard for Māori values around the water and for conservation values around the water," Mr Tomoana said.

"So economics has overtaken environmental safety and we say that good environment is good business."

Mr Tomoana says the water crisis was an accident waiting to happen.

Last year, the iwi successfully appealed a Hawke's Bay Regional Council decision to get rid of a clause which stated there was to be no degradation of Heretaunga Plains and Ruataniwha Plains aquifer systems.

Iwi now say the Regional Council has been reluctant to work with them.

Mr Tomoana says the iwi want to help "but people don't expect that from us, they see that we're a nuisance and in the way, but we're here to help and we haven't been asked".

But a Regional Council spokesperson says they have a "strong working relationship," and invite them to council meetings. There is also a Māori Committee with representatives from Ngāti Kahungunu.