People visiting the Northland holiday hotspot of Mangawhai are being told to stay put - following a sudden early morning tornado

Around three this morning, a line of severe thunderstorms and winds tore through the town and surrounding areas.

Fire and Emergency New Zealand says it received multiple reports of roofs collapsing, trees falling, and windows blowing in.

Two people have been taken to hospital with serious injuries - with a neighbour confirming one was thrown from the top floor of their house.

Meanwhile Northpower says it's restore power to thousands of home - but the main village area and further north towards Waipu Cove remain affected.

It warns people to treat all lines as live.

Northland MP Grant McCallum, says with Auckland Anniversary Weekend, Mangawhai is bulging at the seams - and a number of visitors at the campground have been affected.

He says a large number of the population is there - and they should stay where they are until they get advice from FENZ about what to do.