Civil Defence in Northland and Coromandel are on stand-by as former Cyclone Evan edges closer to the North Island.
MetService is predicting two bursts of heavy rain in the next 24 hours, delivering as much as 200 millimetres to the Far North, with parts of north Auckland and Coromandel also in line for a deluge.
The sting in the tail of the former cyclone is set to deliver heavy rain to parts of the Far North between Sunday evening and 9am on Monday.
MetService duty forecaster Hordur Thordarson says another lashing could hit northern regions and Coromandel on Monday afternoon.
He says the heaviest rain is expected to affect Northland with the largest amounts of 100 - 150mm forecast in the eastern hills from Whangarei northwards.
Mr Thordarson says there are also warnings for the north of Auckland and the Coromandel Peninsula.
Civil Defence in Northland is on standby.
Civil Defence Far North controller Alistair Wells says campers in low lying areas must be prepared for rivers to rise rapidly.
He says the system will hit the eastern Bay of Islands possibly more than anywhere else and those are the catchments from Kaeo through to Otiria and Waiomio for the Far North district.
Mr Wells says they have been hit in the past after cyclones and there will be a watch overnight particularly for Kaeo, Kawakawa, Otiria, Waiomio and the Waikare Valley.
In Coromandel Civil Defence controller, Gary Talbot, is advising Christmas campers not to set up in low lying valleys until Monday afternoon.
He says sudden heavy rainfall in areas of the Coromandel such as the Pinnacles and the Kauaeranga Valley can cause flooding because of the steep terrain and the short distance from the hill tops to the foreshore.
Police are advising travellers to delay their plans until at least early Monday morning, as flash flooding may affect roads overnight.