Van up in flames at Sydney petrol station

A van has been completely destroyed, but the driver has escaped, after it exploded into a ball of flames outside a petrol station in Sydney.

A van has been completely destroyed after it exploded in flames outside a petrol station in Sydney. (AAP)

A van has exploded in flames at a petrol station in Sydney's south, with the driver managing to get out of the vehicle just in time.

The white van caught alight about 6am Thursday on King Georges Road, Hurstville before staff and firefighters cut off fuel at the bowsers to stop the gas station going up in flames.

"We knocked the (van) fire down with foam that covered the fuel to stop it reigniting," NSW Fire & Rescue spokesman Norman Buckley told AAP on Thursday.

While the van was completely destroyed in the blaze, no buildings were damaged, Mr Buckley said.

NSW Ambulance said the driver was able to quickly escape unharmed.

Traffic is heavy and motorists are being urged to avoid the area, Live Traffic Sydney said.