Kevin Bice, 58, was trying to start a borrowed lawn mower in the backyard of the Monkhouse Place house he rents with Scott Dickinson at 4.30pm.

The spark plug arced to the petrol tank and Mr Bice said the lawn mower exploded.

“The tank might have been leaking. I don’t know what happened,” he said.

“It was a wake-up call to me, to anyone who’s got long grass. You can’t stop it once it starts.”

Long, dry grass yard fuelled the fire that started to burn two mattresses standing against the back of the home.

Mr Dickinson said the burning mattresses set fire to the back of the home, damaging the kitchen and the laundry.

Mr Dickinson was in the kitchen at the time, his 14-year-old daughter was outside the house.

Mr Dickinson went to help Mr Bice fight the fire with garden hoses.

Fire and Rescue NSW firefighters arrived within five minutes and 20 minutes later had controlled the blaze.

Mr Bice, who had minor burns on his arm and throat, was taken to hospital for observation of his heart condition. He said he had collapsed twice because of his heart rate was rising.

Mr Dickinson sustained a minor burn to his arm.

Both suffered smoke inhalation.