MetService says the Coromandel Peninsula and eastern Bay of Plenty could be in for more heavy rain this week.

The area has become sodden under days of heavy rain, but conditions were beginning to ease by Friday.

However, meteorologist Angus Hines says another big weather system was due mid next week.

"It's another low coming in from the north, and this one has the potential to pack a real punch once again. It could bring some more heavy rain and some strong winds to the Coromandel Peninsula."

Angus says its path over New Zealand was not yet certain.

"There's a chance that it might swing a little bit away and miss Coromandel, but there's just as much of a chance that it could bring another couple of days of very wet weather to that part of the nation."

Flooding in the Coromandel on Friday. Photo: Supplied/Coromandel's CFM.

The same weather system is also set to drench western Bay of Plenty and the East Cape. The rain is expected to gradually push south into the central North Island, Hawke's Bay, and Wairarapa.

Severe gales were also possible in the central and lower North Island through till the middle of next week.

MetService forecaster Gerard Bellam​ said there was no sign the wet weather was slowing down for some of the country's most popular holiday spots.

'We're seeing an influx of wind and moisture coming in as subtropical weather moves its way down towards us with no indication of any settled period coming soon.

'It's been quite a long spell of unsettled weather which we usually wouldn't see to this extent but what it means is that we're going to be in for a rough ride this January.”

The rain is hitting some of the country's top summer holiday spots, as hundreds of residents from Auckland, Wellington, and Christchurch flock to baches at the top of the South Island, the Coromandel and the eastern Bay of Plenty area.

A slip on State Highway 25, on the Coromandel side near Te Rerenga, during a storm on the peninsula.Photo: Liz Goldsworthy.

The Coromandel Peninsula in particular is reeling after extreme heavy weather brought flooding, land slips, and road closures.

Thames Coromandel deputy mayor Terry Walker says the ocean was 'raging” and it was 'like the middle of winter”.

Thames Valley civil defence controller Garry Towler says a number of local roads were already closed due to slips and the catchments saturated.

"We're expecting these slips and trees to come down for the next four or five days."

If the weather system did arrive in the Coromandel it would "possibly cause further delays and more flooding and further slips".

He advises any holidaymakers returning to the area to "drive to the conditions" and "add time to your journey" because there may well be delays.

The Tapu Coroglen Road had fallen debris during the storm on Coromandel peninsula. Photo: Rhys Forrest.

Meanwhile, locals reported campers from out of town abandoning areas they would ordinarily flock to at the height of summer.

The rain had cut roads around Whitianga but both State Highway 25 and the 309 Road were reopened on Friday.

Bellam says further rain means people in those areas should take extra caution.

'There's been an awful lot of rain in that area. We recorded that in the Coromandel's Pinnacle ranges, 351mm of rain fell in 60 hrs.

'That wind and the rain has saturated soils and sets things up for possible disruption.”

Bellam says the prolonged wet spells were partially caused by a large high pressure system west of the country called a blocking high, which has blocked the movement of weather systems that would normally pass in a few days.

He said those same spells will be less pronounced in the western Bay of Plenty and East Cape, where a heavy rain watch was in place for the weekend.

”That same system hitting the Coromandel looks set to drive more wind and moisture into the eastern central parts of the North Island which means more rain for those communities.”

Overall, he advised holidaymakers to take extra caution until the wet weather spell passes.

'If you're out in those areas, swollen waterways and potentially unstable hillsides will be major hazards if the soil becomes any more saturated.”