Weather: Giant Southern Ocean storm 'still intensifying', will return on Friday

The huge Southern Ocean storm which hammered lower New Zealand on Tuesday isn't finished with us - and will move back in on Friday.

WeatherWatch says the system is "still intensifying", with winds gaining strength around the storm's centre.

But at the same time, the storm is drifting a little away from New Zealand for the next day or two, which will keep the windiest weather confined to around the Southern Alps and Canterbury.

"The latest severe weather update has raised Canterbury High country from watch to a WARNING, with NW gales gusting 120km/h in places today," MetService says.

"Also watch issued [to the] Canterbury Plains and Christchurch for potential severe gales."

The West Coast will also see heavy rain today, with a moderate risk of thunderstorms, small hail and 90km/h gusts.

But WeatherWatch has a message for Kiwis - "don't be fooled by the lull".

"It drifts back on Friday and this weekend it finally crosses New Zealand," it says.

"Because the centre of the low is then moving into the New Zealand area directly, we can expect winds to increase nationwide and rain to move in.

"This action will push heavy rain back into the West Coast on Friday, Saturday and Sunday and incredibly another 300 to 400mm possible over the next few days."

The low is likely to fall apart on Sunday or Monday, to be followed by a cooler change sweeping over the country with a burst of wind and rain. But as early as next Tuesday subtropical airflows may return again with the warmth.