A regular Perth rail commuter says he is willing to take the Public Transport Authority (PTA) to court over a $50 parking fine as there may be a broader problem with the agency's ticketing technology.

Every weekday, Mr Coker parks at the Murdoch train station and swipes his card to pay to park and then again to pay for his fare into the city to work.

But he was shocked when he was hit with a fine earlier this year for allegedly not swiping on to pay the $2 parking fee.

"I distinctly remember doing it on that day," he said.

"And I saw that the [display screen] said that payment had been received OK."

The PTA said there was no record of payment, and because commuters using the ticketing card technology did not get receipts it was Mr Coker's word against the agency's.

It denied there was a broader problem with the ticketing technology.

But the PTA's own records on Mr Coker reveal he is a diligent patron who swipes on to pay for both his fare and parking each day.

Opposition Transport spokesman Ken Travers said the fine should be written off.

"They should be giving a loyal customer the benefit of the doubt, and in this case he's clearly a loyal customer that has regularly paid his $2 every day," he said.

"This is an appalling way to treat your loyal customers that are regular payers."

But the PTA will not budge, and in a letter to Mr Coker has refused to withdraw the fine, even after he wrote to the Transport Minister Dean Nalder pleading his case.

Questions over PTA parking ticketing system

Mr Coker said he had recently experienced other problems with PTA swipe card system, Smartparker, including being unable to swipe off on a machine and being charged a higher default fare that was later refunded.

"I think there's probably a broader problem with the system and I think that's probably being kept under wraps and the public aren't aware of the issues," he said.

Mr Travers shares concerns that there could be ongoing issues with the technology.

"The real issue here, is is there still an ongoing issue with our technology that they're trying to hide," he said.

"I'd invite other members of the public to contact me if they've had similar problems."

The PTA's David Hynes said there was no issue with their technology and a comprehensive review of Mr Coker's case reviewed no fault with the machine on that day.

"I have got a list here of 1,000, more than 1,000 other tags at that machine on that day were successful," he said.

"So there wasn't a problem with the machine so therefore someone who, with the best will in the world, but if they don't do it properly, they haven't tagged, they haven't paid so they get fined.

"Smartparker is a relatively new system, coming up to a year old.

"There were some issues when we started but we found, our studies suggested, that in 95 per cent of the cases the issues were with users who were not familiar with the system and that's why we gave them a long honeymoon to get used to using the system.

"We've ironed all those out, everything's working wonderfully well now."