That accident was blocking the left lane of the clip-on for some time and led to heavy city-bound traffic from as far back as Northcote.
At 5.20pm, another crash - near the Market Rd off-ramp on the southern motorway - caused heavy congestion.
A police spokeswoman said officers were at the scene of the two-car crash, which was blocking the south-bound middle lane.
It is not yet known whether anyone has been injured, but St John are at the scene.
The Fire Service was also called to the crash site briefly.
NZ Transport Agency is urging drivers to expect delays and to take care on the roads.
"Major delays travelling south over Auckland [Harbour[ Bridge,'' NZTA said on its Twitter page.
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The delays may add to the already-expected traffic by those travelling in and around the city to attend the Auckland Lantern Festival, which kicks off tonight at the Auckland Domain at 7.30pm.
People attending the event are being encouraged by organisers to travel by bike, as two valet bike parks next to the festival are being set up.
Auckland Transport said evening stop closures and diversions were being put in place until the last day of the festival, on Sunday.