Watch Jami-Lee Ross' bombshell statement on Simon Bridges in full

National MP Jami-Lee Ross has launched a spectacular attack on leader Simon Bridges and announced he will resign on Friday.

The statement he read to media at Parliament took aim at Mr Bridges over alleged corruption, a lack of popularity with the public and poor political decision-making.

The Botany MP also used the statement to resign as a National MP, and announce he would be running as an independent candidate in a subsequent by-election.

Earlier, the National Caucus met to vote on Mr Ross' future with the party after being blamed for leaking Simon Bridges' expenses to Newshub.

The investigation into the leak couldn't definitively identify the leaker, but the evidence strongly pointed to Mr Ross.

Mr Ross vehemently denies the allegations, and cut across his leader's big announcement by taking to Twitter five minutes beforehand to make stunning allegations of his own.

Newshub.