Vic arsonists set themselves on fire

Three men have accidentally set fire to themselves while trying to start a fire at a supplements store in Melbourne's southeast.

CCTV footage shows three men approaching the Supps R Us store in Harding Street in Bentleigh about 2am on Thursday, with one man carrying a plastic watering can believed to contain flammable liquid.

When the liquid was ignited an explosion engulfed the three men - with one man's clothing catching fire - before the trio fled the business.

It is the second arson attempt at the business in 24 hours after a molotov cocktail was thrown at the store the previous night.

The store recently hired a security guard amid security concerns, 3AW reports.

Victoria Police are investigating a spate of arson attacks against Supps R Us after fires were lit at its Dingley store in December 2013 and September 2014.