A fiery exchange on TV3's The Nation this morning.

Imperial Tobacco's Axel Gietz announced the company wouldn't rule out a fight with the New Zealand government if plain packaging went ahead, before being attacked by Maori co-leader Marama Fox.

Fox joined Dr Gietz on the show and the MP became angry during the discussion, accusing the tobacco spokesman of "peddling death and destruction and misery on our people".

She also compared Dr Gietz to Nazi propaganda chief Joseph Goebbels.

After 17 minutes, Fox took off her mic and walked off set.

Dr Gietz didn't react or rise to Fox's comments.

As Fox made her departing remarks, The Nation host Lisa Owen pleaded for civility, reminding the MP that Dr Gietz was an invited guest.

Earlier on the show. Dr Gietz said a lawsuit against the Kiwi government would be a last resort, but they would defend the right to use their brands.