West Coast authorities will decide this evening about declaring states of emergency as the second former tropical cyclone in three weeks bears down on the region.
Ex-tropical Cyclone Gita is forecast to strike the west coast of the country from tomorrow afternoon bringing wind gusts of over 150km/h in places, heavy rain and northwest swells of 8 to 9 metres.
Metservice meteorologist Nick Zachar said this morning's tracking update showed the brunt of the storm approaching from the top of the South Island, from Westport through to Farewell Spit.
• Wellington mayor warns commuters ahead of Gita
West Coast mayors and officials will meet today at 5pm in Greymouth with Civil Defence staff to discuss the latest weather predictions and necessary actions.
Grey District mayor Tony Kokshoorn said they were still recovering from the impacts of ex-Tropical Cyclone Fehi, which struck at the beginning of February, and the strong wind gusts coming with Gita posed a real danger.
"At the meeting tonight we will make a call about whether or not we need to declare a state of emergency, or a partial one, in advance."
The current predictions were similar to Cyclone Ita, the remnants of which struck New Zealand in April 2014 bringing winds of 130km/h in places, cutting power, and leaving 39 homes in the Grey District uninhabitable.
"The gusts then ripped roofs off houses, and the gusts with Gita are predicted to be similar and hang around for 36 hours," Kokshoorn said.
"The easterlies, as predicted, come off the alps and pick up enormous speed.
"We are really worried about roofs coming off houses.
"Some buildings and trees are still being secured [after Fehi], and there are fears [Gita] will exacerbate those issues.
"We want everyone to be safe and secure all of their stuff."
Revington's Hotel, on Greymouth's main street, had its roof partially pulled off during Fehi.
The derelict building had been earmarked for demolition previously, and was now posing a safety hazard.
"The owners have secured it as much as they can, but it is in the main street so could be dangerous."
Another concern was the former rubbish dump near Cobden Beach, which had its side ripped out by a storm surge during Fehi, scattering tens of thousands of plastic bags along the coast.
Since then the council had begun securing the site by building a rock wall.
"It is much more secure than it was two weeks ago. We are also not expecting the storm surges to be as bad as with Fehi either."
Air New Zealand has warned of "significant disruption" to the domestic network as well as some international services over the coming week as a result of Gita.
Customers are advised to defer travel where possible. This can be done in the same class without fare difference, penalty or service fees until March 1.
Interislander is keeping a close eye on Gita but said at this stage it's expecting sailings to run as scheduled this week.
General Manager Mark Thompson said anyone booked on the ferry over the coming days will be kept up-to-date over the next 24-48 hours.
"We will be sending updates to all customers to keep them informed of potential impacts.
"Safety is our first priority and we will continue to monitor the situation closely."
The category 2 cyclone, which ravaged Tonga and parts of Samoa, southern Fiji and New Caledonia, is expected to track towards New Zealand today while transforming into an ex-tropical cyclone and then a low pressure centre on Tuesday night.
MetService issued severe weather warnings this morning for much of the western parts of the country.
Gita is expected to bring heavy rain causing slips, rapidly rising streams and rivers, and flooding.
Severe gales with damaging gusts are expected, so people are advised to secure property and items that may be blown away by strong winds.
There is also the potential for coastal inundation with high tide overnight Tuesday and before dawn on Wednesday, due to the combination of tides, low air-pressure, strong onshore winds and large waves in excess of 6 metres in some places.
For the North Island, coastal areas from Raglan southwards to southern Wairarapa are most at risk.
For the South Island, the risk of coastal inundation is greatest for areas from Buller and North Canterbury northwards.
Heavy Rain Warning
Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.
Area: Nelson and Buller
Valid: 12 hours from 9am to 9pm Tuesday
Forecast: Expect 150 to 200mm of rain to accumulate west of Motueka,with lesser amounts elsewhere. Peak intensities of 20 to 30mm/hr possible.
Valid: 12 hours from 10am to 10pm Tuesday
Forecast: Expect 150 to 200mm of rain to accumulate about higher ground, and lesser amounts elsewhere. Peak intensities of 20 to 30mm/hr possible.
Valid: 24 hours from 1am Tuesday to 1am Wednesday
Forecast: Expect 100 to 120mm of rain to accumulate.
Area: The ranges of Westland, also the Canterbury High Country and foothills
Valid: 15 hours from 1pm Tuesday to 4am Wednesday
Forecast: Expect 150 to 200mm of rain to accumulate. Peak intensities of 20 to 30mm/hr possible.
Strong Wind Warning
Strong wind gusts could damage trees, powerlines and unsecured structures. Driving may be hazardous, especially for high-sided vehicles and motorcycles.
Area: Taranaki, Taihape, Whanganui
Valid: 10 hours from 3pm Tuesday to 1am Wednesday
Forecast: Severe gale north to northwest winds gusting 120 km/h in exposed parts of North Taranaki, but damaging gusts of 140 km/h in exposed parts of South Taranaki, Wanganui and Taihape.
Area: Nelson and Buller
Valid: 31 hours from 3pm Tuesday to 10pm Wednesday
Forecast: Severe gale east to northeast winds with damaging gusts of 140 km/h in exposed places.
Valid: 12 hours from 4pm Tuesday to 4am Wednesday
Forecast: Severe gale southeasterlies gusting 130 km/h in exposed places.
Area: Westland and the Canterbury High Country
Valid: 14 hours from 11am Tuesday to 1am Wednesday
Forecast: Severe gale southeast winds with damaging gusts of 150 km/h possible in exposed places.
Area: Canterbury from Banks Peninsula northwards
Valid: 8 hours from 7pm Tuesday to 3am Wednesday
Forecast: Severe south to southwest gales gusting 120 km/h in exposed places.