David Seymour is standing by his letter to the UN - now withdrawn.

He wrote responding to an official who'd expressed concerns about the impact of Seymour's Regulatory Standards Bill on Māori.

The Prime Minister says that's a job for the Foreign Minister and Seymour's conceded it's better to a have a single Government response, led by Winston Peters.

Seymour says he still needs to work out how to undo the letter he sent.

"I'll probably have to go through Winston, he probably doesn't want me to write direct to the UN again - I think that would probably miss the whole point of the exercise." 

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