Out-of-town Labour MP Iain Lees-Galloway used a rental car to campaign in the Mt Albert byelection and says it was not paid for from his taxpayer-funded expenses.

But it could have been covered by a colleague's expenses claim.

Mr Lees-Galloway, from Palmerston North, was one of at least 34 MPs from outside Auckland who used taxpayer-funded flights to travel north to support candidates in Mt Albert.

Many then attended meetings related to parliamentary business, allowing them to claim hotel bills, taxis and rental cars on expenses.

The list of campaigning MPs doubled yesterday to cover about a quarter of Parliament's roll call as the public and parliamentary rivals dobbed them in after yesterday's Herald story about how many arranged other legitimate "parliamentary business" in Auckland at the same time, enabling them to claim for expenses.

A Mt Albert woman said Mr Lees-Galloway came to her door while he was canvassing in the Waterview-Oakley Creek area of the electorate.

He had a "very flash red hire car in my street".

Mr Lees-Galloway said the rental car was hired by another Labour MP.

He could not recall who the MP was as "we were sharing rental cars around, and a lot of us were renting cars but not necessarily on our parliamentary expenses - we hired them personally".

Mr Lees-Galloway said that on some days he went to Auckland solely to campaign. He did not claim expenses and stayed with friends.

On other occasions, he was visiting community alcohol and drug centres as part of his associate health portfolio.

He charged for accommodation only once, when the bulk of his time was spent on portfolio business.

Under Parliament's rules, MPs can use their right to unlimited domestic air travel for personal purposes, including electioneering.

But other expenses such as accommodation, taxis and rental cars are not covered if they are incurred while MPs are campaigning for their party.

Labour MP Trevor Mallard said he made three visits to Auckland during the byelection campaign and did a lot of parliamentary business.

He used taxis and rental cars, but as Mt Albert was on the way to the airport, he did not incur any extra expense.

The Herald has asked all the MPs when their parliamentary business was arranged, how much time they spent in Auckland and how much of that time was spent campaigning.

Of the 34, only Act deputy leader Heather Roy has responded.

She said her visit was arranged weeks in advance and she stayed in Auckland for one day.

She joined Act candidate John Boscawen on the campaign trail for an hour and a half over her lunch break.

WHO DROPPED IN

Non-Auckland MPs confirmed as being on the campaign trail.

LABOUR: Trevor Mallard, Parekura Horomia, Iain Lees-Galloway, Damien O'Connor, Shane Jones, Pete Hodgson.

NATIONAL: Simon Bridges, Chris Tremain, Chris Auchinvole, Tony Ryall, Jo Goodhew, Katrina Shanks, Todd McClay, Anne Tolley.

GREENS: Jeanette Fitzsimons, Kevin Hague, Kennedy Graham.

ACT: Heather Roy.