The man sustained facial burns when the fireworks exploded about 12.40 am yesterday.

He had placed the fireworks in a long tube and when he went to light the wick they exploded in his face, police said.

He was taken to the Royal Melbourne Hospital.

Under Victorian law it is illegal to possess or use fireworks without a licence.

Victoria Police spokesman David Spencer said police were investigating.

The accident will also be referred to WorkSafe, which prosecutes the illegal use of fireworks.

The incident prompted another police warning that it is illegal to run backyard fireworks shows.

Police have called on anyone who has purchased fireworks to contact their local police station to organise their safe removal and disposal.

Yesterday's accident is the latest sign of a lucrative underground market in Melbourne for the sale of illegal fireworks, mainly from China.

Last month, five men were arrested after a series of late-night explosions, including one suspected of causing a bushfire.

Two weeks earlier, fireworks were blamed for a scrub fire in the Wombat State Forest.

An indication of the continuing interest in under-the-counter purchasing of fireworks has been the flurry of activity on two internet sites this week, with users exchanging information on where fireworks may be purchased: Melbourne's Chinatown, Richmond's Victoria Street, Footscray Market, Ballarat and Melton.

One reference included details of a trader who keeps the fireworks hidden among food on shelves and who has been caught twice selling fireworks to children.

A password is also given for purchasing fireworks from another trader.

Under state regulations, offenders face penalties of up to $40,000 and jail.

Ambulance Victoria yesterday endorsed the warnings about the danger of lighting illegal fireworks.

Two years ago, illegal firecrackers were thrown into New Year's Eve crowds at Federation Square and another city party zone in Melbourne, injuring four revellers.