Weather worsens for Xmas eve

MetService has issued a severe weather warning for Christmas Eve, with heavy rain over parts of the South Island and a potentially gusty ride for Santa's sleigh.

A low over the south Tasman Sea was expected to bring a period of heavy rain to western parts of the South Island and lower North Island tomorrow.

The heaviest falls were expected about the ranges of Westland and northern Fiordland, where 80 millimetres to 110mm may accumulate over a 12 to 14-hour period, making it difficult for Christmas Eve travellers.

"Heavy rain about the West Coast of the South Island could affect travel there, it could cause slips," MetService duty forecaster Hordur Thordarson said.

There was also a severe weather watch in place with gale northwesterlies expected about inland parts of the South Island, lower North Island and Cook Strait tomorrow.

There were concerns severe gales of at least 110kmh could reach Wellington and the Wairarapa tomorrow afternoon and evening.

"The Rimutakas are one of the places where travel could be difficult ... these winds could potentially cause some problem at Wellington Airport," Thordarson said.

A shorter period of heavy rain was also expected about the Buller Ranges and Tararua Range in the North Island later in the day.