Wellingtonians are being urged to take care on the region's wet roads

Metservice says nearly 30 millimetres of rain has fallen in the city since midnight, with heavy rain due to keep falling through the morning.

Wellington City Council spokesman Richard Maclean says the rain could dislodge man-hole covers.

He says there's likely to be surface flooding around the city and in particular low lying areas.

NZTA says flooding is also affecting northbound traffic on State highway 2 just south of the Silverstream lights.