Maggie Barry has been largely cleared of allegations she misused public money by making parliamentary staff carry out National Party work.
A Parliamentary Services investigation has found no evidence of material or systematic misuse of staff at the North Shore MP's office - though it did find there were times when support staff worked briefly on party or political matters.
These times were found to be "extremely immaterial" - such as receiving membership fees at an electoral office - but would still be deemed inappropriate, the Auditor-General said.
The investigation was requested in February by the Auditor-General after an ex-employee of the Parliamentary Service claimed Barry had made them do political party work during work hours.
Factors which muddied the waters included overtime work by parliamentary staffers, and the unlimited scope of an MP's work. There are no rules against support staff doing party or political work in their own time.
The report also recommended changes that would help ensure greater transparency and clarity around expenditure using the Parliamentary Service's party and member support funding.