Emergency services are searching for an elderly man whose home was engulfed by fire, after a large amount of clutter prevented firefighters from entering the home at Kingsford in Sydney's east.

Key points: Emergency services and police are searching for the elderly man who neighbours said was inside the home at the time

Emergency services and police are searching for the elderly man who neighbours said was inside the home at the time A large amount of hoarded material made the blaze intense and difficult to extinguish

A large amount of hoarded material made the blaze intense and difficult to extinguish The cause of the fire is not yet known

Neighbours told firefighters the man was inside the home on Leonard Avenue at the time of the blaze, around 1:30am.

Firefighters believe the man had been hoarding material, which had built up, leading to an intense blaze, Superintendent Luke Unsworth from Fire and Rescue New South Wales said.

"Thirty firefighters responded to the fire and the single-level house was already totally engulfed in fire when we got there," he said.

The fire quickly took hold because of a large amount of clutter inside. ( ABC News )

"Firefighters tried very hard to make entry into that property but unfortunately the intense fire and the amount of personal items that were there, because it is a hoarder's property, actually prevented the firefighters from making that entry."

A search to confirm if the man was present in his home is underway by NSW Police and emergency services.

The cause of the fire is unknown.

Fire and Rescue NSW has issued its annual warning about winter fire safety — due to the spike of house fires this time of year.

The checklist includes taking care to keep curtains, tablecloths and bedding away from portable heaters and having an adequate number of suitable smoke alarms throughout a home.