According to research published on Monday, the sea level is rising twice as fast as before around parts of New Zealand, particularly its two most important cities - Wellington and Aukland - at risk decades earlier than previously predicted. 

Government-backed data collected from the country's coastline found some areas sinking three to four millimeters a year, which is escalating a long-expected threat.

One expert remarked that the results are "a bit terrifying." 

The findings, part of a governmentally-funded project called NZ SeaRise, are the fruit of integrated work between dozens of local and international scientists over a span of 5 years.

With this data at hand, authorities have less time than expected to introduce climate adaptation plans, including relocating communities on the coast. 

The co-leader of NZ SeaRise, Tim Naish, a professor at Wellington's Victoria University, said that while the global sea level is expected to rise by approximately 50cm by 2100, in some parts of New Zealand the rise could be closer to a meter because, at the same time, the land is sinking too. 

Wellington, the capital of the city, could have a 30 cm sea level rise by 2040. This was a level not expected before the year 2060. This has some environmental disaster implications; with that level of rise, residents in the city could expect a once-a-century flood damage every year. 

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"We have less time to act," Naish said. "You are going to see the impacts of quite damaging sea level rise much sooner than we thought. Roads and properties will be inundated.

"Yes, it is a bit terrifying but there is still time and I think that is the way to look at it."

Auckland - New Zealand's largest city - is very vulnerable. The project predicts that its sea level will rise 50% faster in the city's downtown waterfront and in many central-city suburbs, holding implications for house prices and insurance rates.

The project has developed an online tool to allow residents and authorities to check the forecasts of their coasts, which enables citizens to assess flooding and erosion risks. 

"We still have time, but we don't have time to sit on our hands anymore," Naish said.

"If you're a council representative or you're a developer, or you're a decisions maker in the coastal areas of New Zealand you need to start thinking right now what the plan is for adapting to that sea-level rise."

Jacinda Ardern, the Prime Minister, said adaptation planning was already at work, including budgeting for the relocation of some communities and infrastructure away from vulnerable coastlines. 

"The first port of call isn't necessarily managed retreat because there are a range of options that can be used," she told Radio New Zealand. "We're working alongside local government and insurers to work through who bears the costs of some of these options. The cost that needs to be borne, won't fall on one party."

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