ACT leader David Seymour has fat-shamed his parliamentary colleagues.

While answering questions about appearing in the next Dancing With the Stars, things took a bit of a bizarre turn with Seymour saying there are some people in Parliament carrying more weight than they should be.

"I don't think you need to name the names, I think you guys in the media should get out there with your wide angled lenses and look around.

"We have an obesity crisis in this country, no one's doing anything about it. Well, I am."

Seymour says he believes in free speech and thought confronting obesity and encouraging exercise were more important than offending people.

The ACT leader, who will donate his fees from the show to charity, has described himself as a hopeless dancer, saying his only experience of fancy footwork was an encounter with an Alsatian owned by a Labour voter.

He won't be the first ACT leader to take part in Dancing with the Stars - Rodney Hide gave it a go and his most notable achievement was dropping his partner during a lift.

- with content from NZ Newswire