Mr Myers said the fire fighters were still on scene to make sure the fire was completely extinguished.

"As part of that there's a brick wall that's causing them some issues," he said.

"We've actually organised for an excavator to go out there and knock that wall over to make it safe for fire fighter to go in."

Fire investigators worked into the evening to determine the cause of the fire.

Mr Myers relayed a conversation with a fire fighter on the ground.

"The captain made a comment to me: 'it was pretty daunting having bullets flying out at me from the front window'," he said.

"I'm like Jesus ... could you imagine that? Ducking and weaving bullets coming out of a house?"

EARLIER:

Emergency services have retreated back to an exclusion zone after ammunition inside a burning house in Bethanga has started exploding.

CFA Commander for District 24 Brett Myers said fire crews were alerted to the fire at Beardmore just before 11am by multiple triple 0 calls.

"The information from the callers was that the house was fully involved," he said.

"So we escalated our response with a quite a number of fire trucks from around the area, including trucks from the Rural Fire Service in NSW and trucks from Fire Rescue Victoria."

IN OTHER NEWS:

Mr Myers said he was thankful no one was home at the time.

"But I guess if someone was home, it wouldn't have got so involved so quickly," he said.

Mr Myers said a short time after arrival, fire crew were confronted with ammunition exploding inside the house.

"Thankfully Victoria Police were on scene and in conjunction with them the fire brigade and Victoria Police established an exclusion zone because of the risk of that occurring," he said.

"They just felt like it was more appropriate to pull back a bit.

"But unfortunately it appears the house has been completely burnt.

"Fire fighters will still remain on scene for some time to come to make sure that anything that can be salvaged is and that the fire is completely extinguished."

Mr Myers said the fire would still be burning "quite fiercely" for about two more hours.

The cause of the fire is yet unknown, but Police Victoria and the CFA will conduct a joint investigation.

A 5km smoke advice warning has been issued.

More to come.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: