The ghost of tropical cyclone Evan is set to haunt the Waikato this Christmas with strong winds, humidity and rain.

The weather will get progressively worse as the weekend progresses, Metservice duty forecaster Larissa Marintchenko said.

Swimming conditions at East Coast beaches will also deteriorate as the swell and wind build. Lifeguards are gearing up for swells of more than four metres and treacherous ocean conditions.

The Coromandel Peninsula will bear the brunt of the storm's force with gale force easterly quarter winds expected and rain setting in from Sunday with heavy falls arriving on Monday.

Yesterday, the former cyclone lay about 1000km northeast of North Cape and was moving slowly south.

Over the weekend it is expected to swing southwest towards the North Island, passing close to North Cape on Christmas Eve.

"On Christmas Day the rain should start to ease, especially for Waikato," Ms Marintchenko said.

"It will be occasional rain and showers and on Boxing Day, showers."

It will be the same story on the Coromandel, she said, although the northerly quarter winds will be fresh.

Hot Water Beach lifeguard Gary Hinds is expecting ocean conditions to be "fairly gnarly" as the swell builds and kicks on Sunday.

If the swell gets as big as it's predicted to, more than four metres, he said they may look at closing parts of the beach.

"When those swells come in it turns it into something like a west coast beach - you can be sitting there in no water then all of sudden there's a metre of water around you."

They'll either need guards at the hot rocks stopping people going in because it's too dangerous or just monitoring them.

Despite the likely unsettled nature of the weather on Christmas Day, it should be warm and not particularly windy in most places. "So, Christmas dinner outside isn't completely off the table for everyone," MetService chief forecaster Peter Kreft said.

Forecasting models are predicting ex-tropical cyclone Evan to deteriorate and disappear by Thursday when fair weather should move in for the Waikato.

Nationally, the rain is expected to settle around the whole North Island on Christmas Day, with drizzle in some parts of the south.

MetService said that trough was expected to move northeast and then weaken over central New Zealand on Saturday, followed by another ridge.

Easterly winds will strengthen over the upper North Island during Saturday and Sunday as the low approached Northland. The low should then move away to the west on Monday, but will leave the North Island mostly cloudy and with patchy drizzle in the north.

- © Fairfax NZ News