An electrical short circuit on a power pole was responsible for one of the biggest fires in New Zealand history. 

Fire and Emergency New Zealand (Fenz) has today released its reports into the Lake Ōhau fire, which destroyed 48 homes in the early hours of October 4 last year. 

It took firefighters nine days to fully extinguish the 5000ha fire, one of the worst in modern New Zealand history. 

Fire and Emergency Te Kei Region Manager Mike Grant said specialist fire investigators have determined the fire was accidental and caused by an electrical short circuit on a power pole several kilometres upwind of the village, which ignited dry vegetation below the powerline. 

"Vegetation, terrain, high temperatures and, in particular, severe winds contributed to the rapid spread of this fire towards the Lake Ōhau village and surrounding countryside," he said. 

"Fortunately, no lives were lost thanks to the quick actions from residents of the Lake Ōhau Alpine Village who enacted the community's wildfire plan, and the swift response and evacuations by the Twizel and Omarama Volunteer Fire Brigades and local police.'' 

At the peak of the fire there were 11 helicopters and more than 100 people deployed to support the response. 

Fenz also carried out an operational review into the fire, which considered how fire crews handled the emergency. 

"The review praised the fire crews and residents for their fast actions in the face of fire conditions rarely seen in New Zealand," Grant said. 

"I commend their bravery. Their actions undoubtedly saved lives and several properties that would otherwise have been destroyed." 

The review found the incident was well-managed and had good strategies to ensure the priority was always the people who were impacted by the fire, he said. 

"Recognising the wildfire risk, we have been working with the Lake Ōhau community for more than 20 years to develop a wildfire plan – and providing wildfire equipment and training. 

"We will continue to support them and will be working with them to update their wildfire response plan, incorporating any recommendations from these reports, including factoring in the transient and visitor population of the village. 

"We acknowledge this has been a tough year for the wider community as they have worked through the impact of the fire. We thank them for their patience while our investigators took the necessary time to complete a thorough investigation."