Auckland motorists are being warned to expect delays after police closed the Southwestern Motorway due to an “unfolding incident”.

State Highway 20 was closed heading west at the Onehunga Harbour Rd on-ramp due to “concerns for a person’s wellbeing”, police said.

Westbound traffic has already backed up more than 5.5km from Onehunga to the Auckland International Airport junction with State Highway 20A and SH20.

Police say the incident has now been resolved safely.

“Diversions are being lifted in the area, but motorsists can still expect delays.

“Police would like to acknowledge the public’s cooperation and understanding while we responded to the incident this afternoon.”