Heavy downpours are expected to move along the country today - putting a dampener on the school holidays

MetService says an active front over the Tasman Sea's likely to move eastwards through to Friday, bringing heavy rain to many areas and heavy snow to the south of the South Island.

Watches and warnings are in place up and down the country throughout the week, in places from Dunedin to Northland.

Meteorologist John Law says the wet weather's heading north.

He says the rain will spread across the North Island by the end of the day, and in amongst it will be some heavy thundery falls for Northland, and maybe down to Auckland and the Coromandel.