Most of the South Island is under fire restrictions, or total fire bans, with scorching temperatures of more than 30degC forecast in coming days.
Fire and Emergency NZ wildfire specialist Paul Shaw said there was "extreme concern" about the risk of fires on the east coast and caution and vigilance were needed.
The ground had started to dry out rapidly and severe heat was an added layer of risk.
It was probably the most extreme fire season since about 2018, Shaw said.
"We've got to look back quite a few years before we start seeing conditions like this. We have had them in the past, but again, it's just ramping up this season to look pretty extreme in some parts of the country."
Areas of the highest concern included the Mackenzie Country, Central Otago, southern Marlborough and Canterbury, he said.
"We get a lot of those warm, dry winds coming off the Southern Alps, sweeping down across the Canterbury plains, so we're expecting that to start to dry out significantly in the near future as well."
Total fire bans are in place for parts of inland Canterbury, Otago and Marlborough, as well as Northland, Hauraki and Wairarapa in the North Island.
Some areas of the Wairarapa coast were also a concern - and would likely move to a total fire ban on Monday.
Fire crews were well trained, briefed and resourced - and an incident management team had been set up in mid-south Canterbury to be on standby in case the worst happened, Shaw said.
But the public had a part to play, too.
"If you don't have to light a fire, please don't light a fire this weekend. If you have had fires going, can you please actually check those fires and make sure they're properly out. Any wind can pick up an ember that's still sitting there, carry it into some dry grass, and we've got another fire going."
On Friday, crews were dampening hotspots at two major vegetation fires that occurred the previous day.
A blaze ripped through 10 hectares of Whitireia Park in Porirua's Tītahi Bay, and there was a six-hectare vegetation fire in Kirwee, west of Christchurch - the second big blaze there in five days.
Mackenzie Basin danger
Visitors to the Mackenzie Basin this weekend are being provided with information about the local fire danger in the hope that they will avoid risky activities that could spark a wildfire.
In a statement today, FENZ said it has brought in extra resources to support local volunteer fire brigades, including helicopters with monsoon buckets on standby, automatically dispatching extra crews to all vegetation fires, and pre-positioning an incident management team in Twizel.
Incident controller Rob Hands praised the responsible behaviour of locals and visitors so far this week. Several local contractors have suspended activities including roadside mowing and harvesting that have high risk of sparking a fire. Farmers also contacted FENZ looking for advice about reducing the fire risk associated with their essential farming activities.
Twizel is hosting a rowing regatta this weekend and organisers are making sure that crews and their supporters know about the total fire ban and the need to take extra care and to be alert for any signs of fire. FENZ has set up a community hub in the Twizel marketplace daily to provide advice for locals and visitors.
Restricted fire season in South
FENZ Otago and Waitaki district manager Phil Marsh said despite wet days forecast, the area was so dry the risk would remain and asked people to take steps to reduce the fire risk.
Dunedin, Clutha and coastal Waitaki enter a restricted fire season this weekend, which means a permit will be needed for any open-air fires.
"We've already had a number of significant fires in these conditions this season."
He said people should take extra care this summer, particularly if they were camping or working outdoors, and they could take simple steps to protect their properties if a fire were to break out.
How to reduce fire risk
• Clear flammable material from 10 metres around homes and buildings, and from under desks
• Move firewood stacked against houses
• Clear gutters of dried leaves that can easily catch fire
• Trim trees and bushes and remove trimmings
• Keep grass short - and beware of metal blade mowers that could create sparks.
- RNZ and ODT Online