Transperth has handed out more than 1,300 fines to school students for travelling without tickets, at the same time as offering them free public transport.

Since the start of the school year all primary and secondary students have been able to travel for free, as long as they tag on and off with a student SmartRider.

The government has pitched the program as a cost-of-living measure which could save parents up to $280 a year on public transport fares.

But figures presented to parliament show 1,353 fines have been issued between the start of February and the start of May for those who didn't tag on.

Each infringement would be worth $100.

Officers told not to fine students

The Public Transport Authority said it had "advertised comprehensively" the requirement for young people to have a valid student SmartRider and started the program with a "grace period" to allow for students to be issued with new cards.

"Accurate patronage data is essential in helping us run the network efficiently and track the effectiveness of initiatives like this," spokesman David Hynes said in a statement.

Mr Hynes said the PTA's guidance to officers was that "students travelling in uniform on school days should not receive infringements for ticket-related offences".

Despite that guidance though, he said officers could not exercise discretion when issuing ticketing infringements "in the interest of fairness and consistency".

"In a very small number of cases, where the offenders have had a history of not having a valid ticket and/or repeated misconduct on the network, such as disorderly behaviour, transit officers may issue an infringement to trigger diversionary options (such as engagement with support agencies) available under the Young Offenders Act," he said.

"The number of infringements issued since the start of the program is less than 1,400, which represents just 0.018 per cent of the more than 7.3 million student SmartRider boardings in the same period."

Green MP Brad Pettitt, whose question in parliament revealed the tally of fines – as well as 741 handed out to young people during a period of free transport during summer – said he was surprised how high the tallies were.

"You've got government talking about saving families money, around kids fares and public transport, but then you've got 2,000 families copping a $100 fine during a cost-of-living crisis," he said.

"It would have been much fairer and much more reasonable to at least give warnings, and certainly encouragement towards SmartRiders."

Fines 'counterproductive'

The PTA did not answer questions from the ABC about how many infringements had subsequently been appealed or cancelled.

"Individuals who receive infringements can lodge an appeal, and each case is assessed on its merits," Mr Hynes said.

Dr Pettitt said he hoped Transport Minister Rita Saffioti would step in to reverse the fines and refund those who had already paid them.

"This idea that you jump straight in and start fining children is deeply counterproductive," he said.

"What you want is people seeing public transport as a good, easy, friendly alternative to using cars. And unfortunately, I think this just makes public transport one of those things that you're in danger of actually children having bad experiences with [and] not using later in life."

A period of free public transport for all West Australians between the end of December and the end of January resulted in 3,971 fines being issued. 

That period was credited with increasing patronage by 40 per cent above the previous summer.