Sydney's Opal card scammers put on notice

Thrifty Sydney public transport users exploiting a ticketing loophole to score cheap weekly travel have been warned that the jig is up.

Transport Minister Andrew Constance has announced a crackdown on commuters "Opal running" between light rail stops and train stations to manipulate the ticketing system.

Opal fare rules allow people to travel for free for the rest of the week after clocking up eight paid journeys.

As a result, vast numbers of commuters have been running, riding or skating back and forth between stations to "max out" their Opal cards with cheap trips to reap significant savings.

"What people are doing is tapping on, tapping off, attracting the eight journeys, and then travelling the rest of the week for free on longer trips," Mr Constance told reporters in Sydney on Monday.

He said the scam was seeing some 60,000 Opal transfers recorded at stations in and around Pyrmont on Mondays, which plummeted to just 100 by Friday.

In a bid to stamp out the practice, the number of transfers needed to make a journey has from Monday jumped from three up to seven, making it much harder for users to fill up their cards.

The ruse, which had taken energetic card holders just 90 minutes to pull off, will now take up to six hours, Mr Constance said.

"We're going to clamp down on that loophole and we're going to stop people from doing it," he said.

"My message to Opal runners is stop wasting your time, stop wasting your breath.

"It's a practice which is unacceptable, and as a result we're going to see people stopped from engaging in this behaviour on our network."

Mr Constance said the loophole was leeching up to $2 million dollars in lost public transport revenues every year, which could be pumped into improving services for travellers paying their fair fare.

He said regular ticket holders "playing fair" would not be disadvantaged by the changes, saying racking up the number of transfers needed to game the system was a significant undertaking.