Traffic was backed up on Auckland's Northern Motorway after a crash near the Victoria Park tunnel.

The two northbound lanes between the tunnel and the Harbour Bridge which were blocked by the crash have since been cleared and traffic had returned to normal.

The NZ Transport Agency advised motorists to consider using SH16/18 as an alternative.

At 4.30pm NZTA said the crash had been cleared, but warned motorists that traffic heading north was "very heavy" back to Mt Wellington.

There was also a crash on St Lukes Rd just before the North-Western Motorway on ramp, which blocked the left turn lane and bike lane for a time.