Anzac weather: Long weekend under threat from heavy rain, thunderstorms

Parts of New Zealand are set to be hit by heavy rain and thunderstorms at Anzac weekend with the far south to feel the impact.

MetService says the long weekend will bring mixed weather throughout the country as a front moves its way across New Zealand. This will develop in the south on Friday and move north on Saturday. 

"Those attending the Six60 concert at Eden Park [in Auckland on Saturday] should prepare for the odd shower," the forecaster said in a statement.

"Anzac Day dawn services around the country should stay mainly dry, but Auckland, the lower North Island, and Christchurch could see a few showers."

Late on Thursday, MetService says heavy rain and thunderstorms are possible in Fiordland and the Westland ranges. On Friday, the far south will be affected by big waves.

"A risk of thunderstorms travels with the front, with the possibility of peak rain rates of 10-25mm an hour," MetService meteorologist Alwyn Bakker warns.

"Heavy swells with a very long period of 18-20 seconds will affect the west coasts of both islands over the weekend. Waves of up to 9 meters are possible in the Far South from Friday evening, moving up the coast from then, gradually lowering to 4 metres off the Auckland west coast on Saturday. 

"Long-period swells can create strong and dangerous rip currents with a high beach run up, so care is advised for those visiting west coast beaches over the long weekend."

WeatherWatch says the front is the result of a storm in the Southern Ocean, with strong winds blasting over Australia's Tasmania and heading towards the South Island.

"After this has passed another low on Monday will fire up a colder, more wintry, change for the south of NZ."