National Party MPs have voted to expel Jami-Lee Ross from caucus.
Leader Simon Bridges said the National MPs voted unanimously.
"It's the strongest possible action the caucus could take. We are not going to tolerate the kind of appalling behaviour of Jami-Lee Ross."
"The lies, the leaks and other matters as well are entirely unacceptable."
Mr Bridges said the allegations were "baseless", "entirely false", and he invited the police to investigate.
Mr Ross had made allegations of electoral fraud against Mr Bridges, over donations made by a Chinese businessman.
National MP for Botany, Jami-Lee Ross, will be laying an official police complaint against National Party leader Simon Bridges tomorrow, in which he'll allege electoral fraud.
Mr Ross also told media this morning he would resign as a member of Parliament on Friday, sparking a by-election for the Botany seat.
Mr Ross said he would run as an independent.
The investigation into who leaked details of National Party leader Simon Bridges' expenses pointed to MP Jami-Lee Ross leaking the information.
The PWC report said it had not identified the leaker with certainty, however, "the evidence we have points to Mr Ross".