The Prime Minister's been caught calling ACT leader David Seymour an "arrogant prick" in the House this afternoon. Jacinda Ardern quickly apologised - and David Seymour accepted, wishing her a merry Christmas.

The unfortunate muttering came hours after the government announced the departure of three ministers, who will hang up their hats at next year's election, as well as three backbench Labour MPs.

The Prime Minister announced the exodus this morning - ahead of her planned Cabinet reshuffle early next year.

Here's our deputy political editor Craig McCulloch.