The wild weather hitting much of the South Island and the lower half of the North today, is expected to pack a punch.

There's a number of warnings in place for various parts of the country.

Torrential rain and thunderstorms are expected to hit the West Coast in particular until tomorrow morning.

MetService meteorologist Tom Adams said these warnings are a bit more than your average weather advice.

He said usually a warning is issued when you can expect 100 millimetres of rain in 24 hours - this event could bring as much as 400 millimetres.

Northern Canterbury, Marlborough and Wellington can expect winds of up to 150 kilometres an hour later this afternoon.

Meteorologist Lisa Murray said this type of weather feature deepens so rapidly and has an explosive development.

Murray advises to tie down the trampolines, fix any loose roofs, and be wary of debris flying from earthquake demolition sites.