Speaker Trevor Mallard has stepped up security to ensure that Botany MP Jami-Lee Ross will not have access to any National offices when he returns to Parliament next month.
The new restriction, on the ground floor of Parliament House, will apply to all MPs who are not in National, not just to Ross who was expelled by National in October.
The move comes two weeks before Ross is due to return to Parliament from extended medical leave and the summer break. Ross has been allocated an office in Bowen House, well away from National Party offices.
National occupies offices on the ground floor, second floor and third floor of Parliament House but restrictions on access applied only to the second and third floors. They will now apply to all its offices after the move initiated by Mallard.
A spokesperson from the National Party referred all queries to Mallard, who declined to comment.
But it is understood there have been some concerns within National about Ross' return and what access he would have.
Mallard and the Parliamentary Service general manager are responsible for the welfare of all people working in the parliamentary complex.
Responding to the National Party lock-out, Ross said in a statement: "The National Party ignoring me didn't seem to last long.
"I'm sorry the Speaker and taxpayers have had to go to unusual lengths because the National Party doesn't want it's members interacting with other MPs - they're also now segregated away from Labour, Green and NZ First MPs.
"Those National MPs that have maintained contact with me are still welcome at my office for a cup of tea whenever they want."
The National caucus expelled Ross last year after being accused of disloyalty to leader Simon Bridges and leaking travel expense information.
In the ensuing days, Ross released conversations with Bridges that he had secretly recorded discussing party donations, he was publicly accused by several women of intimidating and bullying behaviour - which he has denied - and was sectioned to the mental health facility at Middlemore Hospital after he contemplated killing himself.
Last week, Ross said that he was ready to return to Parliament, and that he wasn't after revenge, but wanted to serve the interests of those in his electorate.