According to the Press Assocation, West Anglia Great Northern (WAGN) said it was ordering cycles off peak period morning trains into Cambridge for "reasons of safety and passenger comfort."
But a spokesman for the Cambridge Cycling Campaign said it would mean more cars on the roads of one of Britain's most congested cities and inconvenience scores of people who regularly travel to work or school by train and bike.
More than a quarter of peaktime journeys in Cambridge there are made by bike.
WAGN claimed cyclists were happy with the new arrangements and no-one would be inconvenienced.
But the Cambridge Cycling Campaign said it had received 40 or 50 calls from angry cyclists, many of whom claimed they would now be forced to drive into the city.