It means all fires in the open air are forbidden, including rubbish fires, bonfires, backyard braziers, fireworks and cooking fires.
"The forecast for a hot, dry long weekend with increased winds means a complete fire ban is the safest option," said Auckland principal rural fire officer Bryan Cartelle.
Blazes have threatened homes on Great Barrier, and scrub fires have devastated hundreds of hectares around the Waiouru and West Melton army training bases after live firing exercises went wrong in tinder-dry conditions.
Environmental Defence Society chairman Gary Taylor said the forecast for fine, dry, sunny and windy weather for at least the next 10 days in Auckland created a genuine crisis that put the environment and people at risk.
"I am especially concerned about the risks for our extensive regional parklands, including the Waitakere and Hunua Ranges."
The MetService forecasts the warm, dry weather is set to continue well into next month, sparking fears the worst is still to come.
The Fire Service has been kept on high alert this month, battling blazes on several fronts.
It's been the worst fire season in four years, according to national rural fire officer Murray Dudfield.
Northland, Auckland, north Waikato, the central North Island, Hawkes Bay, Wairarapa and Manawatu have been affected worst, he said.
The fire risk is very high or extreme in many cases.
Rural fire authorities around the North Island remain on a "briefing watch" and are monitoring things on a daily basis.
Clear skies, low humidity and some wind results in the "elevated" fire risk where extra care is required.
The National Institute of Water and Atmospheric Research says North Island soil moisture levels are a lot drier than normal for this time of year.
"It's incredibly dry," said Niwa climate scientist Andrew Tait.
"East coast of the North Island, around Auckland, Waikato, Bay of Plenty, are starting to think about water restrictions [and] farmers are thinking about options to bring in supplementary feed, etc."
Northland's councils, major industries and big water users are being urged to closely monitor their water intake and prepare for shortages and restrictions unless there is significant rain in the next two months.
A fire ban has been in place for weeks in the Christchurch region, which has suffered several major scrub blazes this month.
Two houses have been destroyed, 18,000 laying hens incinerated, and hundreds of hectares of farmland scorched.
Canterbury fire crews remain on high alert, although the Fire Service says the rest of the South Island is at low risk. For the rest of the country, however, there is little respite on the horizon.
"For at least the next week or so, it'll stay hot and dry," says MetService meteorologist Dan Corbett. "It might be great for holidaymakers and kids looking forward to the last couple days before going back to school, but it's not so great for the farmers and firefighters."
Mr Corbett also warned that an easterly wind likely across the northeast of the North Island could fan any fires that take hold.
"It won't be until the end of next week that we will see a hint of moisture creep in from either the west or the north to try and break it down.
"What would be wonderful would be to get an easterly in February to provide some relief."
Crews are continuing to monitor hotspots on the Pouto Peninsula, south of Dargaville, after a major scrub fire burned 200ha of forest. It was brought under control on Thursday after burning for two days.
The army plans to continue holding most of its live firing training exercises despite the hot, dry conditions.
But it will hold off at West Melton in Canterbury while an investigation is under way into Wednesday's inferno there, which ignited during live hand grenade training at a Burnham rifle range.
That blaze followed a fire the previous day that destroyed 350ha of scrub on training land around the Waiouru base in the central North Island after an exercise by Singaporean armed forces.
Yesterday, Acting Chief of Army Brigadier Peter Kelly apologised for the "disruption and the angst" caused to local residents by the Canterbury fire.
The police have said arson charges could result if reckless action by the army was proved.
Selwyn District Council principal rural fire officer Wilson Brown estimated the Defence Force would face a bill of about $200,000 for the cost of tackling the fire.
A Defence Force spokeswoman confirmed a court of inquiry would be held into what caused the inferno.
But in the meantime, live firing would go ahead as planned on other military bases, "based on risk assessment procedures already in place".
Defence Minister Jonathan Coleman has said he is "very concerned" about the two army fires.
Rainfall rates
To date for January
6mm - Auckland, typical average 61mm
11mm - Hamilton, typical average 82mm
4mm - Tauranga, typical January rainfall average 78mm
19mm - Napier, typical January rainfall average 67mm
