PM Jacinda Ardern would have tried to facilitate proxy vote for Jami-Lee Ross, if he had asked

Prime Minister Jacinda Ardern says she would have tried to facilitate a way to cast a proxy vote for former National MP Jami-Lee Ross if he asked.

But speaking to media this afternoon, Ardern said neither she, nor the Labour Party, had been approached by Ross.

Yesterday, NZ First decided to exercise the proxy vote of Ross while he was away from Parliament.

"The party wishes to make clear that its decision to accept Mr Ross' proxy, until such time as he revokes it, is done solely on the grounds that the electors of Botany gave a clear expression of their will at the 2017 General Election when they elected him with a significant majority," leader Winston Peters said.

Peters later told media National should use the waka-jumping law and "get down off its high horse".

Last week, the National Party refused to vote on Ross' behalf in Parliament.

Ardern said she did not believe this was a deliberate tactic by New Zealand First to undermine National.

"My understanding is Jami-Lee Ross made the request – obviously he needs to have his vote cast while he is not in Parliament and he made the request to NZ First and they accepted."

She said that was "perfectly reasonable" and she had no problems with that.

He said there had been cases before when MPs have been expelled by their caucus and other parties have cast their vote – "for me this is just an issue of democracy".

Asked if Labour would have cast his vote if Ross had asked, Ardern said he didn't ask.

"But I think I would have tried to facilitate a way for the vote to be counted.

"As I say, this has happened in Parliament before – it's simply a logistical matter of ensuring the people who voted for an MP can still have their vote cast on their behalf in Parliament."

When asked about NZ First's decision yesterday, a spokeswoman for Ardern said it was a "procedural matter" and the Prime Minister would not comment further.

Speaking to media yesterday, Peters said the people of Ross' Botany electorate "deserve to have their voices heard".

Ross yesterday tweeted: "While I remain on leave on medical advice, it is important my constituents in the Botany Electorate continue to have a vote cast on their behalf in Parliament. I appreciate NZ First supporting Botany by accepting my request to cast a proxy vote."