Heavy rain and strong wind's made landfall in the South Island - causing power outages and a road closure

State Highway Six between Haast and Makarora is shut with surface flooding, while more than 600 South Canterbury properties are without power.

MetService meteorologist John Law says the poor weather's expected to hang around in the South Island and lower North Island until tomorrow night.

He says heavy rain warnings are in place for the Tararua Ranges, with heavy wind watches in place for Wellington and Wairarapa until tomorrow morning.