National Party leader Simon Bridges said there is "an area of grey" in terms of what constitutes political and non-political work by parliamentary staffers and he welcomed scrutiny by the review into bullying at Parliament.
"Where there is a parliamentary purpose, it is clearly acceptable," Bridges told the Herald.
"But it is really important the Parliamentary Service ensure that MPs and staff know where the line is so that the rules are followed.
"That does require Parliamentary Service to make sure they are educating and showing us the way."
He was commenting in the light of claims by a former staff member of North Shore MP Maggie Barry, that staff were expected to conduct party-political work such as writing the MP's regular column including on the Northcote byelection and pamphlet for a National Party conference for over 60-year-olds.
The staff member concerned told the Herald he had complained to Parliamentary Service that in some weeks up to half of his work was party work.
He made the claims when Parliamentary Service was looking into an employment dispute in August involving another staff member who accused Barry of bullying and harassment.
Neither works for Barry any longer.
Bridges said he had had no cause to have concern over Maggie Barry's management of staff.
"She denies the allegations. They were investigated by Parliamentary Service and they found there was no bullying or harassment. "
He welcomed the wider review commissioned by Speaker Trevor Mallard to examine bullying and harassment at Parliament - which will invite confidential submissions from current and former staff going back to 2014.
"Parliament and its MPs and staff are in an environment like no other. It is robust and demanding but none of that means we can be complacent," said Bridges.
"We do want an environment where staff who have got concerns feels free to come forward and raise them."
He would welcome more scrutiny by the review on what was political work and what wasn't.
Mallard declined to comment.
Maggie Barry disputes all allegations and said Parliamentary Service had looked into them and "there was no finding that bullying or harassment had occurred".
"The issues have all been resolved professionally and by mutual agreement. I have wished the employees concerned well and so I am surprised they are being repeated in a partial, selective and incomplete way," she said.
Electoral law expert Andrew Geddis says that MPs pressing their staff into doing political work gave them a far greater advantage in elections than non-MPs and the situation may need closer scrutiny.
"Taxpayer funding to hire MPs' staff is given so that they can do their jobs as elected representatives, not to help them win re-election," said Geddis, a professor of law at Otago University.
"If it gets misused for party purposes, sitting MPs get a massive advantage against their unfunded challengers."
Parliamentary Service, the employer of MPs' staff, needed to be on guard to prevent it from happening.
Geddis said allegations on misuse of parliamentary funding were not new.
In 2005 Auditor General Kevin Brady had investigated claims that parties were using parliamentary funding for political advertising.
"It may be something similar is needed in this case," Geddis said.
Brady found that parties in Parliament had unlawfully spent $1.17 million on what he deemed to be political advertising – most of which was on Labour's pledge card.
Most parties repaid the funds but Parliament also changed the rules so that in future, the types of expenditure previously found to be unlawful, came within the rules.
Only advertising explicitly seeking or discouraging support for a party or candidate or explicitly seeking funds cannot not be paid by Parliamentary Service.
Another electoral law specialist, Graeme Edgeler, said staff were allowed to be political to quite a large extent and it would boil down to what been in their employment contract.
A press secretary working for the National Party would be writing political press statements attacking the Government and calling for, say, Minister Iain Lees-Galloway to be sacked.
That would be a parliamentary staffer paid by Parliamentary Service doing a clearly political job.
"You are allowed to employ people to be highly partisan…according to parliamentary rules, the employees that you have can be expected to be highly partisan."
He said there would be limits about how partisan a staffer could be and that assisting an MP for a parliamentary purpose would exclude seeking votes for the MP or fundraising.
But Edgeler pointed out the advantage that Act, for example had over The Opportunities Party. Act, which received 0.5 per cent of the vote in the 2017 election, now got taxpayer funding for a staffer to write highly partisan press statements, but TOP, which got 2.44 per cent, didn't.