Update 5.45pm - Congestion is now easing after faulty railway lights caused delays throughout the city.

A number of motorists travelling towards BayPark roundabout in both the northbound and eastbound lanes reported traffic was 'crawling' at the time.

However NZTA says the road is now clearing.

"The railway signals have been repaired and congestion is easing."

Earlier:

Motorists throughout the city are facing a number of delays, following reports of faulty railway lights.

A caller to the 0800 SUNLIVE news hotline says traffic is built up heading towards the Baypark roundabout from Maungatapu.

"We are moving, but slowly."

Further delays have also been reported near the Kaimai Ranges.

NZTA says the delays have been caused by a fault.

"Due to faulty railway lights traffic is congested in this area. Avoid the area or delay your journey if possible."

There is no indication as to when the fault will be repaired as of yet.