Buses travelling across the Sydney Harbour Bridge to the city experienced delays of up to an hour and a half during the Monday morning peak due to heavy traffic after roadworks closed parts of the CBD.

Bus passengers catching services in the CBD were delayed by up to 30 minutes, the Transport Management Centre said.

The traffic volume eased by mid-morning, the centre said.

Passengers can use their tickets on Sydney Trains, on the T1 North Shore Line between Chatswood and the city and on the City Circle as an alternative, the centre said.