A rampant beach blaze allegedly sparked by fireworks being let off in blustery conditions will take another three days to bring under total control, fire chiefs say.

The fire at Pegasus Beach north of Christchurch ignited around 7.30pm on Wednesday night and was quickly fanned by high, warm northwest winds over a 5km, 200ha-front.

As the blaze ripped through sand dunes and seaside pine trees, it bore down on Woodend Beach township and forced the evacuation of the camping ground.

More than 130 people took flight in the night as firefighters battled to keep it at bay. No properties were damaged.

From first light yesterday, four helicopters with monsoon buckets, guided by a fifth chopper, and two fixed-wing aircraft, attacked the fire’s flare-ups and hot-spots from the skies.

This morning, Fire and Emergency New Zealand (Fenz) Incident Controller Graeme Knight predicted that the fire would take another three days to extinguish.

A plane sprays water over the fire. Photo / George Heard

Crews are today still dealing with multiple hot spots but Knight said he’s confident they will stay within the containment line.

One helicopter remains on site, helping firefighters on the ground with mopping-up.

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With the fire spreading over a long area, Knight said crews would be on the ground all weekend.

“I would be picking three days, we should have it pretty well cleaned up, not to say there’ll be the odd hot spot that rears its head after the fact.”

A helicopter carrying a monsoon bucket goes to drop water on the blaze near Pegasus Beach. Photo / George Heard

Canterbury Police rural area commander Inspector Peter Cooper earlier confirmed fireworks caused the blaze.

Two young people were spoken to, with one being referred to Youth Aid.

“We are pleased to have been able to quickly identify those allegedly involved and we hope this brings some reassurance to the community,” Cooper said yesterday.

“It has been established the fire caught following a firework being let off.”

Flames stretch from the scene of the Pegasus Beach fire on Wednesday night. Photo / Supplied

Te Whatu Ora Waitaha Canterbury medical officer of health Dr Ramon Pink said exposure to smoke can worsen health conditions such as asthma and heart disease.

“People affected by the smoke should close windows and doors, stay inside if it’s safe to do so, and avoid or reduce outdoor exercise.”

Anyone experiencing health issues from the fire should phone their usual general practice team in the first instance, he said.

“For families returning to homes or holiday accommodation after the fire, it is important to know the smell of smoke in your properties presents no serious threat to health.”