NSW State Transit has defended its trial of sponsored wi-fi on 50 public buses as concerns mount over how much personal information the internet service proposes to collect from commuters.

iTnews reported Friday that the ‘Catch’ wi-fi service, operated by APN Outdoor, had wide-ranging terms of use indicating it “may” collect personal information including “name, address, date of birth, location details, drivers licence details, photographs, video, credit card details, employer and other details”.

The terms indicated such information could be disclosed to third parties to tailor advertising and “offers” to passengers.

The broad terms generated a backlash on Twitter and saw NSW Greens MP and transport spokesperson Dr Mehreen Faruqi criticise the planned trials over the weekend.

"It is deeply concerning that the personal information of commuters will be harvested for targeted advertising," Faruqi told Fairfax.

"If the cost of installing the system is being recovered by passengers becoming advertising targets, this must be made crystal clear up front."

A State Transit spokesperson told iTnews today Catch is “purely an opt-in service”.

"In the first instance the passenger will agree to general use terms and conditions; they will not be required to enter any personal information," the spokesperson said.

"Customers may be asked to provide personal details, including submitting photos or videos, if they voluntarily choose to enter in to a promotion, competition or other transaction on the Catch network in the future.

"All information collected is handled in accordance with the Privacy Act."

The spokesperson said the transit authority was “happy to support the APN Outdoor trial of Catch technology on State Transit buses”.

“At this stage, the trial is ongoing and the outcome of the trial will determine any further roll-out to the rest of the transport network,” the spokesperson said.

Buses equipped with the Catch technology are understood to be operating out of the Ryde, Waverley, Leichhardt and North Sydney depots.

However, they are not designated to particular routes, meaning passengers across Sydney's bus network could have an opportunity to trial Catch, should they choose to do so.