The race to become the Labour party's next leader steps into overdrive from today with Tauranga set to get in on the act next week.

For the first time, the contenders for the leadership of a major party are running public campaigns, seeking donations and using avenues including their own websites, Twitter and traditional advertising to pick up votes.

The three Labour Party contenders will square off at the Wesley Centre from 7pm next Wednesday.

Grant Robertson, David Cunliffe and Shane Jones will deliver their pitch to lead the party at the first of a series of town hall meetings in Levin today and thousands are expected to attend a nationwide roadshow over the next few weeks.

In a vital part of New Zealand's first mass participation process for electing a political party leader, the three contenders for the Labour leadership will square off at a Husting Meeting next Wednesday at the Wesley Centre from 7pm.

The Electoral College for the Labour leader was triggered with the departure of David Shearer last week and comprises three sections – party members, caucus members and affiliated unions.

The 12 Husting Meetings over an 11-day period are a chance for voters from all three sections of the Party to meet and question the candidates, and to hear them speak. The Moderator for the meeting will be Susan Vize.

The meeting is expected to last two hours and features speeches from the candidates.

People who are members of the NZLP and affiliated unions are invited to attend, and need to bring evidence of their membership. Members of the public can join the Labour Party at the meeting and attend.

A preferential system is being used, listing the candidates from one to three and to win, a candidate has to get 50 per cent of the vote plus one.

If a winner isn't clear from the first count, the least popular candidate drops off and the other two then battle it out.

The result will finally be known on September 15.

It's expected around 50,000 Labour members and union affiliates will vote for their favourite in a preferential voting system.

The winner has to get 50 per cent of the vote, plus one.

The Tauranga meeting starts from 7pm at the Wesley Centre, 100 13^th Ave Tauranga (registration from 5.30 for members).