Civil Defence groups and councils in the North Island are bracing themselves for the arrival of the tail-end of tropical cyclone Lusi, which is forecast to bring severe gales and heavy rain to many areas from Friday.
MetService and the Ministry of Civil Defence are closely monitoring Lusi, which by Thursday morning had moved to the south of Fiji. Forecasters say it is no longer posing a threat to Pacific nations but its winds are intensifying.
The cyclone killed three people in Vanuatu.
MetService meteorologist Dan Corbett told Radio New Zealand's Morning Report programme on Thursday that Lusi will be strengthening over the next 24 hours, reaching New Zealand late on Friday. "We are in its cross-hairs: it is heading our way for this weekend," he says.
Mr Corbett says the north of the North Island will feel the brunt of the storm first. The bad weather is then expected to move down the North Island and could reach the upper South Island on Sunday.
Mr Corbett says most places, including the east coast of the South Island, will feel Lusi's effects.
Civil Defence director John Hamilton says they're asking people to be prepared. "There's a chance this thing with its high rainfall and winds is likely to isolate people," he says. "It might result in power outages in places, so it's an opportunity for people to check that they've got the appropriate sort of kit in the house and are ready to go."
The Coastguard's northern regional manager, Graham Petrie, says boaties should secure their boats on Thursday and stay off the water this weekend.
The Auckland City Council says some outdoor weekend events have been cancelled and the Bay of Plenty Regional Council is warning against weekend fishing trips and says boats need to be moored securely.
Waikato Civil Defence co-ordinator Lee Hazlewood says months of dry weather have left debris in creeks and waterways that could be washed downstream and pose an extra risk in a flash flood.