An unauthorised climber on the Sydney Harbour Bridge has forced police to shut numerous lanes on the bridge, causing severe traffic delays in both directions.

A police spokeswoman says multiple reports were received around 4:30am this morning and negotiations with the man are ongoing.

The Traffic Management Centre have warned motorists saying, “It doesn’t look like it’s going to have a quick resolution … it’s basically going to throw peak into chaos for anyone coming into the Sydney CBD.”