"The vapours have ignited upon starting it," he said.

"Three young kids were in the boat as well. They immediately jumped out of the boat into the water."

Leading Senior Constable Scherger said the eldest girl had burns on her legs and face.

"Dad has burns to the arms and the other girl had minor burns to her legs," he said.

The Bendigo Advertiser was asked to leave the scene by the property owners when staff arrived.

UPDATE, 11.15am: Four people suffered burns after in boat explosion at Lake Eppalock on Saturday morning.

Ambulance Victoria spokesman John Mullen said there were four people on board the boat when it caught fire.

“Apparently when it’s ignited they’ve jumped into the water,” he said.

“A man in his 30s and three girls aged between 10 and 13 suffered superficial burns.

"The 13-year-old had some facial burns and looks likely to be the only one needing transport. She’ll probably be taken to Bendigo.

“The others are being treated at the scene for superficial burns.”

Mr Mullen said three ambulance vehicles attended and there was a helicopter on standby but it was not required.

He said the injuries suffered were not as serious as emergency services first thought.

CFA and police also attended.

Police say the incident is a timely reminder for people to vent their boats before use.

Emergency crews were called to Hazlett Avenue, Kimbolton, soon after 10am.

More to come...