WELLINGTON (Reuters) - A bush fire on New Zealand’s South Island spread through thousands of hectares, destroying property and forcing the evacuation of about 100 homes, officials said on Wednesday.

The fire that started at Pegion Valley in Nelson on Tuesday doubled overnight to spread over 1,870 hectares within a perimeter of 20 kilometers, the Nelson Tasman Emergency Management Office said in a statement.

More than 100 homes have been evacuated or self-evacuated, the statement said, and people were being sheltered at civil defense centers. Authorities declared a civil defense emergency in the Nelson-Tasman region.

Several homes have been burned down although there have been no reports of casualties or injuries so far. Strong winds have been fanning the flames and firefighters struggled to reach affected forest areas.

Officials said 12 fire crews worked overnight to control the fire, and 10 helicopters and two planes were being used on Wednesday to control the blaze. It could take up to four days to extinguish the fire, firefighters said.