Forget the lottery, buy a myki ticket and hit the jackpot.

That's the word riding the rails after three commuters each had more than $167,000 credited to their smartcard accounts in yet another embarrassing glitch.

The trio received the unexpected windfall as the roll-out of Victoria's smartcard public transport ticketing system descends further into farce.

Kamco, the company responsible for the myki software, has blamed a fare calculation programming error for the mix-up and is working to identify others who may have been affected.

Opposition transport spokesman Terry Mulder said the system was "an absolute disaster" and commuters could now have a punt on its failings.