No one should fear the outcome of negotiations with Maori over water rights, Prime Minister John Key says.

He has again given an assurance that water ownership isn't an issue and says governments have recognised for more than 20 years that Maori have rights and interests.

"To argue someone owns water is nonsense," he said on TV One's Q&A programme on Sunday.

"People have rights and interests and those are negotiated iwi by iwi and river by river...I don't think people should be fearful of those negotiations."

Mr Key says his government negotiated the Waikato River co-management agreement with Tainui, and that was an example of how claims are settled.

"The government has demonstrated over the last four years that the right way to resolve these issues is through negotiation - it's been done in a calm and considered and appropriate way, and that's the right way to do it."

The Maori Council has asked the Waitangi Tribunal to recommend delaying the partial privatisation of four state-owned energy companies until water rights are resolved, and says it plans to seek a High Court injunction after the tribunal issues its report in about a month.

Mr Key says the government is expecting legal action.

"Someone will probably take us to court to test their rights," he said.

"And anyone can claim ownership, but whether they would be legally successful is a very different matter - in my view they wouldn't be successful."