Crews battle factory fire in Sydney's Northern Beaches

Fire crews have brought a massive factory fire on Sydney's Northern Beaches under control.

The fire at a surfboard factory in Brookvale sent large plumes of black smoke billowing into the air for hours on Sunday afternoon as dozens of firefighters worked to contain it.

Firefighters were called just before 5.30pm AEDT and rushed a dozen trucks and about 40 firefighters to the scene on Orchard Road.

"We are in what we call defensive positions, extinguishing this fire from the outside," Fire and Rescue NSW Superintendent Adam Dewberry said, not long after they were called to the blaze.

"We understand this to be a surfboard-manufacturing premises. Surfboards can have a high fuel load, different products and resins used in the construction, and the foams used."

There were no initial reports of injuries, but paramedics treated a teenage boy for minor burns to his hand.

Police and the NSW energy authority were also supporting the firefighters.

Emergency services began wrapping up at the site about 7.30pm.