If that was the case, those rights and interests needed to be determined before anyone started taxing water.
Until a discussion had been held about water rights and interests, any potential tax should be off the table.
"You can't start charging for something you don't own."
Any discussion about water rights, interests, management, quota, ownership, pricing or quality must involve hapu and iwi and the same went for any potential land tax, he said.
Ms Fox said Labour announced it would not bring in any new taxes or levies in its first term of government, beyond those already announced.
Labour had changed its mind on other taxes, so it should now commit to where it stood on the water tax.
People deserved to know what they were voting for and Maori needed to know about Labour's plans for a water and a land tax. A land tax could hit Maori landowners hard, and they needed to be told the details, she said.
"It's all very well and good saying 'trust us'. Maori have trust issues when it comes to Labour."
Maori deserved to be represented by Maori MPs who would stand up for their rights and interests and not kowtow to their party's position, Ms Fox said.
"We're not against looking at the issues around water, but what we are opposed to is riding roughshod over the interests of Maori."
Mr English said on TVNZ1 Q+A Labour's water tax randomly adopted a punitive attitude towards one selected group, something which Labour had itself expressed.
"They have said if we disagree with this, we'll double it. The real issue is the pollution going into the water and the extensive work and investment going on in New Zealand now to manage that.
"We don't need the tax. It's a poor tool. And we want to work with the community they are provoking."
The policy was causing distress, and not just in the farming community, he said.
Horticulture people, and the people working in those industries, had changed their behaviour through five or six years of intensive work.
Labour and the Greens had just discovered the issue of water quality and were using it cynically, Mr English said.
Labour policy
The royalty for irrigation water is expected to be about 1c-2c per 1000 litres. The royalty for bottled water is expected to be on a per litre basis. It will be proportionate and fair. Levels will be set following consultation and revenue will largely be returned to regional councils.