ACT Party leader David Seymour is brushing off an insult from the Prime Minister.

Speaking under her breath today in Parliament today, Jacinda Ardern called him an arrogant prick, but it was picked up by Parliament's microphones.

Ardern texted Seymour to apologise, saying she shouldn't say such things, and he replied wishing her a Merry Christmas.

David Seymour says the comment isn't a big deal in comparison to other things he opposes, like Three Waters.

"The great irony is that now I actually have got her to apologise for something, so that's progress. I just wish that she'd apologise for a few other things."

LISTEN ABOVE

• Watch: 'Such an arrogant prick'- PM lashes out at David Seymour
• Jacinda Ardern calls David Seymour an 'arrogant prick', apologises for comment