Judith Collins says the one thing she'd change about her political career is leading the National Party.

The Senior MP has announced she's leaving politics after 24 years, in a career that included 18 different ministerial portfolios.

In 2020 she had a brief stint leading the party, and lost the election to Jacinda Ardern. 

She says stepping up was a bad move.

"And I knew it was a hospital pass now, and I still did it, even though my husband was saying - don't do that. And I thought, well, who's going to do it if I don't?"

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• Judith Collins announces retirement from politics
• 'A formidable politician': Barry Soper on the highs and lows of Collins' political career