David Seymour won't be letting his new role stop him from speaking out

The Act Leader has been formally sworn in as Deputy Prime Minister.

He takes over from New Zealand First Leader Winston Peters and will remain in the position until next year's election.

Seymour says he still has responsibilities as Minister for Regulation.

He says he knows one of the things he'll be judged on over these three years, is how much red tape he gets rid of.