Blaze next to chemicals threatens stretch of city

A car thought to have been set ablaze by fireworks next to a building storing ammonium nitrate could have levelled two to three kilometres of Dunedin, says a senior fire officer.

The building was well sealed, but "the flames were leaping up through where the ventilation in the side of the roof was", said Senior Station Officer Rob Torrance.

The fire in the abandoned car caused the evacuation of about 10 residents from apartments in Fryatt St early on Saturday.

Witnesses had seen youths using fireworks in the area.

Firefighters responded to hundreds of fires on Guy Fawkes Night.

The southern fire communications centre took 412 emergency calls and crews attended 266 fires in three hours in Christchurch alone.

Most of the callouts were small hedge, scrub and sand dune fires.

Burned-out fireworks were left strewn across cities, requiring huge clean-ups for council staff and locals.

In Auckland, Inspector Andrew Brill said the police northern communications centre handled 395 disorder-related incidents - about 30 per cent more than expected on a normal Saturday night.

Nationwide, incidents included:

* A lit sparkler was thrown into a postbox in Dunedin, burning an estimated 100 pieces of mail.

* At Queenstown's Wakatipu High School, a classroom window was broken and a firework thrown inside. It landed on a chair, where it smouldered but was extinguished before any real damage was caused.

* In Wellington a scrub fire on Mt Victoria, believed to have been caused by stray fireworks, threatened onlookers at the official Guy Fawkes display. The fire was brought under control within an hour.

* A train passenger heading to Paraparaumu was put off the train after setting off a firework in a packed carriage as it passed through a tunnel about midnight.