MetService says storms rolling across the country as a result of a significant low that are moving over from Australia will ease for most parts later this evening.

Meteorologist Lisa Murray says it triggered thunderstorms from Northland to Coromandel and heavy rain in Southland, particularly in the Buller and Nelson regions.

But she says it's begun to lose steam.

The system's moving to the north east over the country and should move off overnight with remnants left only over the northern areas of the East Cape.

Later in the morning showers will die away with a south westerly and fine breaks covering the country.

The bad weather's also causing gridlock on some Waikato Roads, with 11 crashes in the district over a five hour period today.

Police say routes to holiday destinations in the Coromandel and Bay of Plenty are particularly affected, as these are also routes transited by heavy transport vehicles servicing the ports of Tauranga and Auckland.