Gisborne is set to get another dousing of rain on Monday night, after torrential downpours caused flash flooding in the area on Sunday.
MetService said the wild weather across many parts of the country in recent days was caused by a complex low-pressure system slowly moving across the North Island.
The system is continuing "to inch its way across" the country, with eastern and lower parts of the North Island still in the path for more heavy rain.
"Further rain is expected over the areas of Gisborne that experienced heavy rain and flooding over the weekend, however the heaviest of the rain is expected to be farther south, where flooding is also possible," said MetService meteorologist Mmathapelo Makgabutlane.
Angus Hines, another MetService meteorologist, said a heavy rain warning was in place for southern Gisborne, as well as the Wairoa District, from 6pm Monday until 10am on Tuesday.
"It will be wet overnight tonight - we could see around 100mm or so in that region," Hines said.
A heavy rain warning is also in place in the Wairarapa, excluding the Tararua District, with up to 80mm of rain forecast about the hills and ranges. A strong wind watch is also in place there, as well as in southern Manawatu, Horowhenua and the Kapiti Coast.
Hines said Wellington had strong southerly gusts of up to 130 km/h this morning, with strong southerlies expected "for a little while yet".
Gales of up to 120 km/h are forecast for exposed parts of Wellington until 9pm on Monday.
Heavy rain is also expected in Wellington and Marlborough this afternoon.
Earlier on Monday, the wet weather led to parks and some roads being closed in Marlborough, after up to 145mm of rain fell in the eastern Marlborough Sounds area.
The Marlborough District Council said levels of the Taylor and Omaka Rivers were "up significantly", though rainfall had now "dropped back to a few showers".
A heavy rain watch remains in place in the region, and a strong wind watch is also in place in Northern Marlborough.
The Kaikoura coast and ranges also have a heavy rain warning in place, with the MetService warning the rain could cause streams and rivers to rise rapidly.
"Surface flooding and slips are also possible and driving conditions may be hazardous."
Makgabutlane said the eastern South Island was on a "clearing trend" for the rest of the day, with many inland parts of the lower South Island remaining under low cloud.
She said the low-pressure system is set to move away from the country on Tuesday and will briefly be replaced by a ridge of high pressure.
"This sees a period of more settled weather before the next round of wet weather arrives from the other direction, impacting western South Island from late Wednesday."
