A rush-hour breakdown on Auckland's Harbour Bridge has left northbound traffic queues of several kilometres.

Traffic on the motorway is snarled back to Spaghetti Junction after an earlier breakdown on a northbound lane of the Harbour Bridge.

The breakdown has since been cleared but the New Zealand Transport Agency has tweeted a warning about long queues back to Spaghetti Junction.

A video shows traffic moving at snail's pace across all lanes.