It is expected to mean more than 300 trains being removed from the timetable to help save money when passenger numbers are still just 10 per cent of normal.
Scottish Government support to ScotRail and Caledonian Sleeper in the year to March is expected to nearly double to almost £1 billion.
The changes follows the number of carriages on trains being reduced this month, and services being reduced from 90 to 80 per cent in December.
The latest cuts will see fewer peak hour services and fewer trains running after 7pm across the network.
Last trains will leave earlier, such as 10.15pm on the Glasgow-Edinburgh main line in both directions – an hour and a half earlier than currently.
Remaining services are aimed at key workers, such as NHS staff travelling to hospitals.
Non-essential travel, including between council areas, is banned.
ScotRail said: “With a focus on continuing to provide a safe and reliable service, particularly for key workers and in support of the vaccination rollout, the number of services is being reduced to 65 per cent of pre-pandemic levels, while delivering 72 per cent of seats.”
Operations director David Simpson said: “We have constantly adapted our timetable throughout the pandemic to reflect restrictions in place at any given time, allowing those travelling to be able to rely on ScotRail, and these alterations will again ensure that we deliver that critical service.
"There will also be minimal change for those currently using our services, as we have matched changes with the current demand.
“Like any business during the pandemic, we need to continue to make sensible financial decisions, and reducing the number of services means a reduction in costs for the taxpayer, while continuing to deliver a safe and reliable rail service.”
Scottish Liberal Democrats transport spokesperson Carole Ford said: “Many key workers are dependent on rail transport so it is important the level of service continues to meet their needs.
"There must also be a recognition that season tickets are now operational on far fewer trains yet the prices are unaltered.
"It is unreasonable to expect customers to pay the pre-pandemic price for a reduced number of available trains.”
Graham Simpson, her Scottish Conservatives counterpart, said: “ScotRail have a difficult task to balance the need to run trains with demand, which has fallen off a cliff during the pandemic.
“I can understand why they are cutting services but they are receiving millions of pounds to keep them running.
“I don't want to see any more cuts because some people still rely on the trains, even during lockdown.”
Scottish Greens’ transport spokesperson John Finnie said: “Whilst it would be easy to be critical of a further reduction in services, what’s important is that everyone who requires to travel within the current guidelines can do so safely.
"The challenge may well be reversing these declines and ensuring sufficient, safe capacity to deal with a return to previous numbers carried.”
Colin Smyth, transport spokesperson for Scottish Labour, said: “With more and more trains being axed, passengers will fear that some services simply won’t return even when we move out of the pandemic.”