Bus passengers in Melbourne are still being overcharged because of a myki glitch first identified by the public transport ombudsman more than three years ago. The glitch causes some travellers to be incorrectly charged for travelling in zones one and two when they should be charged only for one zone.

The total amount of money passengers have been overcharged since myki was switched on will never be known because instances of overcharging are only recorded when a member of the public tries to get their money back.

The contract to run myki is due to be awarded by June next year. Credit:Rebecca Hallas

Public transport users say it is likely the small amounts of money gleaned from myki accounts each time the glitch strikes have gone unnoticed by most people, who do not routinely review their myki statements. One regular bus passenger approached Fairfax Media after being overcharged 15 times in one year.

Public Transport Ombudsman Treasure Jennings released the industry watchdog's annual report on Thursday.