Nearly 30 cyclists have been fined this morning for running red lights or not wearing helmets during a large police crackdown near the Pyrmont Bridge, renewing debate about riding in the city.

About a dozen police, some on bicycles, were targeting cyclists near Union and Murray Streets between 7.30 and 9.30am.

Just the ticket ... a cyclist falls foul of the police on Pyrmont Bridge.

Fifteen riders were fined $59 for not wearing helmets, while 14 were fined for running red lights.