The myki system operates by commuters touching their cards on and off at a scanner, which automatically deducts the appropriate fare. If users do not touch off, they will be charged a full fare.

"Commuters who forget to scan their new myki smart cards when leaving their local platform to go home will be charged a penalty of $4.96, according to Public Transport Minister Lynne Kosky," Mr Rich-Phillips said.

"The myki card forces users to touch on as they enter a train station, tram or bus and they must also touch off or be charged the higher fare.

"The process of touching off consists of removing your myki from your purse or wallet, stopping and holding it against the sensor before passing through the gateway.

"What's going to happen when 200 myki users try and touch off through the four little exits [at Dandenong station] at the same time?

"I imagine there will be a considerable amount of irritation as many commuters rushing off the platform will have to queue five or 10 minutes to leave the station."

Myki spokeswoman Jean Ker Walsh defended the system that "takes around a second to touch on or touch off".

"We do not expect touching off to further delay customers exiting the station.

"With myki, customers only need to remember three things - top up, touch on and touch off and that's much simpler than choosing from the 16 different Metcard products currently available."

Mr Rich-Phillips floated an e-tag style system, similar to the ones used on cars on CityLink and EastLink, in which commuters could walk through a scanner and the myki card would automatically register. He said the station would need to undergo a significant upgrade for the current myki system to work.