The number of fines issued to cyclists for breaking red lights more than doubled last year, according to recent Garda figures.
571 cyclists were penalised in 2017 compared to 276 in 2016.
However, the number of fines issued to motorists for parking in cycling lanes dropped from 205 to 165.
Dr Paul Corcoran, Chairperson Dublin Cycling Campaign, thinks the rise in fines for cyclists is down to better enforcement.
He said: "I think there was more traffic gardaí graduated last year so they are tackling more issues on the streets.
"There is a minority of people who do break the lights, I see it myself, but that goes across the board to all traffic users.
"What I would be concerned about is that we are not really tackling the issue of parking in cycling lanes, that is still a huge problem so we are forced to go out into the main traffic, which is dangerous."
He also welcomed the enforcement of the rules.
Mr Corcoran told the Irish Times: “In fairness with the pedestrian streets, people sometimes don’t have a choice because of the lack of infrastructure and cycle lanes available to actually cycle down a street.”