Transport officers are being recruited to combat widespread fare evasion on Auckland trains, but a public transport group claims they will be powerless to detain or arrest freeloaders.

Auckland Transport is also tackling attacks on trains by graffiti vandals by gating eight more stations. Currently, only Britomart, Newmarket and Manukau stations are gated.

This follows an incident last weekend at the new Parnell station where a gang of vandals pulled the emergency door release to get inside the train and caused damage.

We think having staff on the trains with legal powers will help make the trip safer and more comfortable for all our passengers

It was the first time vandals have tagged a train at a mid-station platform. Normally, it happens at end of the lines stations, like Swanson and Onehunga.

The so-called graffiti artists often operate in groups and are in and out in a couple of minutes. They are not interested in causing trouble to commuters or staff, an Auckland Transport spokesman said.

As part of Auckland Transport's safety and fare enforcement (SaFE) project, Auckland Transport has begun a recruitment drive this week for 18 transport officers.

Fare evasion is believed to account for 4 per cent to 6 per cent of ticket revenue on trains. Vandalism on trains costs about $500,000 a year.

The transport officer role has been created in response to legislation due to be passed by Parliament next month.

Auckland Transport metro operations manager Brendon Main said the legislation is expected to give officers the power to enforce fare payments and issue penalty notices.

The 18 officers will work initially on the western line to test the new legislation and scope of the role.

"We think having staff on the trains with legal powers will help make the trip safer and more comfortable for all our passengers. We think they will deter the freeloaders who think they can travel without a ticket," Main said.

The Public Transport Users Association said transport officers are a step in the right direction but they will be low paid and not have the power to detain and arrest people or demand proof of identification.

Spokesman Jon Reeves said they are basically parking wardens on trains when what is needed is a dedicated public transport police unit in Auckland and Wellington.

"Railway police are used in the UK, Switzerland, Germany and other first-world countries. With growth on Auckland trains running at 20 per cent a year it's time we implemented the same style of policing," Reeves said.

Trains were generally safe to travel on, said Reeves, but with growing violence from high school children and graffiti attacks, policing on trains needs to be seriously looked at.

Work has started gating Manurewa and Henderson stations. Parnell will get gates by the end of the year. Gates at Otahuhu, Middlemore, Papakura, Papatoetoe and Glen Innes are expected to be completed by early next year.

When the eight new stations are completed, about 90 per cent of trips will be through a gated station.

SaFE is a joint commitment between Auckland Transport and Transdev to deliver initiatives to improve customers experience, increase security and safety and reduce vandalism and fare evasion by the end of 2019.