It's been a stormy night in the upper North Island

A tornado's hit the Hamilton suburb of Nawton -- downing trees, flipping barbecues, throwing a trampoline into powerlines, and leaving about 100 homes without power.

Parts of Auckland and Northland have faced thunderstorms and gales.

MetService meteorologist Lewis Ferris says while there's some more bad weather on the way, things should improve over the long weekend.

He says high pressure's building so generally through the weekend the weather will be settling down.