People who buy paper single, return, weekly, monthly and date-to-date tickets are encouraged to migrate to myki from July 17.

Paper periodical tickets will no longer be available from September 24, although tickets already bought will be valid for use until expiry.

Paper tickets for single and return service tickets will remain until further notice. Victorian Greens leader Greg Barber said the amount of unstaffed stations around regional Victoria was a cause for concern.

On the Bendigo line, Macedon and Malmsbury stations are not staffed, and Gisborne, Riddells Creek and Clarkefield have part-time staff.

"The real losers under myki are seniors, students and health care card holders in small towns where the stations are not staffed," Mr Barber said.

"Every option available to them under myki is more complicated and costly than buying a ticket from the conductor or on the train."

A Public Transport Victoria spokesman said there would be more staff temporarily at these stations to help with the changeover.

"PTV and V/Line customer service staff will be at stations along the Bendigo Line to provide information and advice to customers about myki, from topping up, to touching on and touching off," he said.

A V/Line spokesman would not confirm if there are any plans to put permanent staff on currently unstaffed stations.

"There will be myki mates at major stations and additional staff on trains during its introduction," he said.