The four -- Andrew Little, Nanaia Mahuta, David Parker and Grant Robertson -- were at Labour Party HQ this morning to sign a Code of Conduct and go through the campaign rules.
They can use the MPs' unlimited air travel allowance to travel around the campaign -- but have to pay for any other costs themselves including hotels, taxis and meals.
Mr Robertson said the use of air travel was within the rules. "[The taxpayer] is not picking up the tab for the contest. We are obeying the rules we have around airline travel. Everything else is our own cost."
Mr Little said the contest did involve meeting the public, which was part of an MP's job.
"There is a balance there."
The candidates can fundraise for their campaigns -- Mr Robertson's supporters are seeking donations for his while Mr Little has said he had already received several offers of help, both practical and financial.
All will have to disclose any donations of more than $500 after the campaign and the use of trusts to disguise donors is now banned after David Cunliffe used one last time.
Mr Little and Mr Robertson said the contest had to be respectful because the contestants all had to work together afterwards and had the common aim of rebuilding Labour.
Mr Parker said it would be competitive "but that doesn't mean it has to be war without guns".
The last minute entry, Ms Mahuta, who put her hand up after Mr Cunliffe pulled out, said the main focus was moving forward. "Labour members are no strangers to robust exchanges of ideas, on leadership views and how things can move forward."
She said she might be perceived as an underdog "but I see myself as an equal in this contest".
By Claire Trevett of the New Zealand Herald
