The Onehunga off-ramp is now open and traffic is beginning to ease following a crash on Onehunga Mall Rd this afternoon.
NZ Transport Agency said traffic congestion remained backed up to Plunket Ave at 6.50pm and thanked commuters for their patience.
Earlier this afternoon police reported that a vehicle collided with a pole on Onehunga Mall Rd, resulting in the city-bound Onehunga off-ramp from State Highway 20 being closed.
Rush-hour traffic was advised to expect significant delays and motorists were asked to avoid the area if possible.
NZTA posted on Facebook that northbound congestion on the Southwestern Motorway was backed up to just before Puhinui Rd after the incident.
An earlier video tweeted on the agency's social media account showed slow-moving traffic in northbound lanes.