A CFA volunteer, a resident of the Midland Holiday Park at Lima South, and the caravan park owner reported a fire at a caravan shortly before 5pm.

A CFA spokesman said fire spread quickly to a further six caravans and annexes with 48 fire-fighters from 12 brigades protecting adjacent structures as residents were evacuated.

There were reports of gas bottles exploding but it’s unclear if it caused the fire or whether bottles exploded in the fire.

The spokesman said the cause of the fire was unknown but it’s not believed to be suspicious.

He said fire investigators would arrive on-scene this morning to try and ascertain how the fire started.

Ambulance Victoria spokesman John Mullen said there were no injuries but four people, a two women and a man in their ‘60s and a man in his ‘50s were emotionally distressed and needed to be checked out by paramedics.

A fire crew remained at the park overnight to monitor the blaze, which was declared safe about 8.40pm.

State Emergency Service volunteers supplied lighting overnight and a local power company isolated the power.

The caravan park, situated about 30 kilometres south from Benalla on the Midland Highway, is still open for business.