The decision was made last year by outgoing First Minister Nicola Sturgeon to freeze ScotRail fares until the end of March 2023 to support rail users during the ongoing cost-of-living crisis.
The freeze is set to expire on March 31 but the Scottish Government is yet to confirm what will happen to fares from April 1.
ScotRail fares are typically subject to an annual inflation-linked increase which takes effect in January.
Rail users are worried they could be hit with shock fare rises
As part of its response to the cost-of-living crisis, the Scottish Government promised a freeze lasting three months.
Scottish Liberal Democrat leader Alex Cole-Hamilton is now calling for the freeze to be extended.
He said: “Rail users are worried they could be hit with shock fare rises in less than a week unless the Government leaps into action.
“It’s completely unacceptable that this deadline has been allowed to creep closer and closer without any clarity about the future of fares.
“I am calling for this freeze to be extended to the end of the year to protect rail users during this cost-of-living crisis.
“Up until now the Scottish Government’s promises to rail users have been as solid as steam.
“For instance, last year’s flagship sale cut the price of fewer than 1% of tickets sold. Passengers deserve a concrete date for the removal of peak fares too.
“Now that ScotRail is in public hands we need long-term ticketing solutions to encourage people to rely on rail travel, backed by trains that actually run on time.
“Scottish Liberal Democrats will offer a public transport system that works for all communities, for all ages and for the climate.
“That’s why we want to see fares cut, new options for two/three-day-a-week season tickets and for the Government to work with councils to explore new lines, particularly in areas where public transport links are poor.”