Northlanders are being urged to get ready for what could be one of the biggest storms to hit New Zealand so far this century, according to a private weather forecaster.

The newly named Cyclone Gabrielle has formed in the Coral Sea, northeast of Australia and is currently heading towards New Zealand.

Its exact path is so far uncertain but it is likely to bring heavy rain to Northland and eastern parts of the North Island from Sunday onwards.

WeatherWatch.co.nz said the northern half of the North Island was especially exposed to the growing cyclone.

“We don’t say this lightly, but this is looking like one of the most serious storms forecast for New Zealand so far this century,” the forecasting company said.

Civil Defence Northland said it was “looking more and more likely” Cyclone Gabrielle would bring severe weather to the region.

It was expected to lie north of the country by late in the weekend and could bring severe gales to Northland on Sunday, along with “very large” waves and a storm surge along northern and eastern coastlines from Sunday into Monday.

Wave heights off the northwestern tip of Northland were expected to reach 8 metres by Tuesday.

MetService was confident warning amounts of rain and easterly gales would hit Northland from Monday to Tuesday.

There was, however, still uncertainty around the exact path of Cyclone Gabrielle, so Northlanders should keep up to date with the latest weather information by radio, online at www.metservice.com/warnings/home, or the Civil Defence Northland Facebook page.

The latest warnings come just 10 days after a State of Emergency was declared in Northland ahead of a forecast severe storm, which came with Northland’s first-ever red heavy rain warning.

However, the worst of that weather system bypassed the North and instead hammered Auckland and the Coromandel for the second time in a week. State Highway 1, the main route to Northland, remains partly closed at the Brynderwyn Hills due to slips.

Kelly Stratford, Far North District Council deputy mayor and chairwoman of the Northland Civil Defence Emergency Management Group, urged Northlanders to enjoy the “beautiful weather” while it lasted today and probably tomorrow, and prepare for potential heavy rain from late Sunday onwards.

“Be assured that Northland Civil Defence and council are taking steps to prepare and are monitoring the situation. If you live in an area that does flood, make sure you have petrol in your cars, LPG for cooking and batteries for your torches,” she said.

“Secure objects like trampolines and report any blocked drains today by lodging a request for service with your council, especially in urban centres. Clear out your guttering if you haven’t already and familiarise yourself with your community.”

■ Go to getready.govt.nz/en/emergency/storms for tips on how to prepare for a storm. Northlanders can also go to www.nrc.govt.nz/civildefence to check which areas could be flooded and to see if their area has a Community Response Plan. Response plans include the locations of evacuation centres if they are needed.