Most New Zealanders will see rain over the next 24 hours as a large low crosses the North Island according to WeatherWatch.co.nz.

Heavy rain is spreading into western parts of the South Island today and about Nelson, while heavy rain will also move in to Northland and into other northern regions tonight.

Overnight tonight rain clouds will spread almost everywhere, with rain also moving into Southland and Otago during Thursday.

Rain is likely to turn to snow at higher altitudes in the South Island, which may affect some alpine passes.

Heavy rain warnings are currently in force with watches also being issued.  Click here to see them.