Services in areas including Manchester, Liverpool, Blackpool and the Lake District will be affected by the reductions, which the operator says will improve reliability.
The introduction of new timetables in May has resulted in travel chaos on the lines, with 14% of Northern services cancelled and 25% at least five minutes late on Tuesday this week.
Northern managing director David Brown apologised for the “disruption” and “inconvenience” to passengers.
“We’re truly sorry for this and are working hard to fix this,” he said.
“We are absolutely committed to resolving the service issues and the interim plan will help ensure we start to get back on track and start to give customers more certainty around the services we operate.”
The operator says it will continue to run more trains than it did before the timetable change, and plans to get back to a full timetable by the end of July.
The changes will affect 165 out of 2,800 daily services, the operator said, and will “stabilise” services, eventually reducing the number of late-minute cancellations.
Transport Secretary Chris Grayling this week criticised rail companies for “wholly unsatisfactory levels of disruption” following the introduction of new timetables.
Labour have said “a failed and unpopular system of rail privatisation” is to blame for the continued problems.
The disruption follows a major timetable shake-up in which saw 400 new daily services added to daily schedules.