Winston Peters takes brazen dig at Simon Bridges' leadership credentials in Parliament

Deputy Prime Minister Winston Peters has taken aim at Opposition leader Simon Bridges in Parliament.

Mr Bridges and the National Party have been tested over the last week, following accusations of electoral fraud from rogue former National MP Jami-Lee Ross.

During a particularly heated question time, Prime Minister Jacinda Ardern became visibly more frustrated with Mr Bridges' questioning over the fuel tax.

Mr Peters took the opportunity to take a dig at Mr Bridges' leadership, which has come under scrutiny in the Ross saga and a subsequent investigation into the culture of the National Party.

He used the point of order procedure to say: "Mr Speaker, it's one thing for the leader of the Opposition to be shouting out and protesting during an answer, but all the contenders can't do it as well."

The comment implied that his role as leader of the National Party was fragile and could soon be up for debate.

Speaker Trevor Mallard then rose to his feet to make Mr Peters apologise for the comment.

"The most experienced Member of the House knows he should not use the point of order procedure to be disorderly himself," he said.

Mr Peters then stands to apologise, but not without his signature grin.