Ms Louw said the Marlborough Sounds, Nelson and Buller could expect strong to gale southeast winds on early Sunday morning.
A significant amount of snow was also likely on the ranges of North Canterbury and Marlborough, between Culverden and the Wairau Valley.
"In this area, significant amounts of snow are likely to accumulate above 500 or 600 metres from Saturday night to Sunday morning, likely affecting the Lewis Pass," she said.
Heavy rain would hit Wellington and the Wairarapa overnight Saturday and into Sunday, Ms Louw said.
However the low effecting the country this weekend would move northeast tomorrow, and will be replaced by a ridge of high pressure, meaning fine weather for most by Monday.
Move your clocks forward
Summer is nearing as clocks move forward an hour tonight for daylight saving.
Daylight saving starts at 2am Sunday morning, when 2am becomes 3am.
Clocks will go back again on April 5 next year.
The Fire Service urged people to test their smoke alarms at the same time they move their clocks forward.
"The simple fact is that smoke alarms save lives," the service's fire risk management national advisor Todd O'Donoghue said.
Tsunami warning sirens in Christchurch and Auckland will be tested on Sunday, as part of their twice yearly checks which coincide with Daylight Saving.
Christchurch's tsunami warning siren system will be tested at 11am, and the sirens will sound for one to two minutes. The sirens will be heard within a few blocks of the beach along the coastline from Waimairi Beach to Sumner, as these are the areas most at risk from a possible tsunami, the Civil Defence said.
In Auckland, sirens will be tested on the north and west coasts on Sunday.
The test sequence will be three sets of tones, each signalling a specific action and each will sound for one minute with 15 seconds between each set, the Civil Defence said.
Residents were advised that in an emergency, tones will sound for longer.
Civil Defence are advising residents not to panic when they hear the sirens, as they are just tests to ensure systems are working.