Wellington has been drenched by heavy rain while heavy fog has caused delays at Christchurch Airport this morning.

A low which was sitting to the west of the South Island over the weekend is now making its way over the North Island, bringing heavy showers to much of the lower North Island.

Police central communications spokesperson Sergeant Andy Dow said there is low visibility and surface flooding and asked drivers to take extra care.

He advised motorists to drive to the conditions and put their headlights on.

TranzMetro has replaced all services on the Johnsonville line with buses due to a slip on the tracks.

MetLink Wellington said all bus services are running up to 15 minutes late due to the weather, while Wellington Airport is advising passengers give themselves more time to reach the airport.

WeatherWatch.co.nz Facebook Reader Andrew Bennett reported a heavy downpour in Wellington around 7:15 this morning.  He said the maximum rainfall rate was 25.2mm/hr.

Meanwhile, flights seem to be on schedule at Christchurch Airport.  Several domestic flights faced short delays thanks to a thing blanket of fog early this morning.

If you need more information, you can check the airport’s website at http://www.christchurchairport.co.nz/en/flight-information/