Police say there have been no reports of extortion linked to spate of licensed-venue arsons

Police say they are yet to identify a motive behind a series of arson attacks on licensed venues in Melbourne in recent weeks.

Several restaurants and clubs in inner-Melbourne suburbs have been targeted by arsonists, but investigators say none of the owner of the venues have reported extortion threats.

South Yarra restaurant France-Soir was the latest venue to be targeted earlier this week.

Detective Inspector Chris Murray from the Arson and Explosives Squad told ABC Radio Melbourne a suspected arson attempt on the restaurant was thwarted when passers-by noticed the alleged would-be offenders.

“They saw two individuals loitering near the premises, saw a jerry can in the back and called it in,” he said.

The restaurant’s owner, Jean-Paul Prunetti, said he did not know why his establishment was targeted.

“We were a bit shocked because I never thought it would happen to us, but it just happened and that’s it,” he said.

“We’re not really understanding what happened really.”

Police have charged a 31-year-old Sandringham man and a 22-year-old Mooroolbark woman with offences including possessing an imitation firearm, drug possession and using fraudulent registration plates.

Police arrested two people in relation to a fire at a Southbank bar last week. (ABC News)

Investigators are at a loss to explain the recent spate of arson attempts, saying extortion was “a logical assumption”, but there was no evidence yet to back up that theory.

“Each and every owner who’s been subject to an arson attack and attempted arson state they haven’t been extorted, which is puzzling,” Detective Inspector Murray said.

“The motive is unclear and we’re trying to understand what that motive is but the owners have been very co-operative and say they haven’t been threatened.”

Chris Murray, from the Arson and Explosives Squad, says police are still trying to establish a motive. (ABC News)

Investigators say several arrests they have made have helped them identify a common thread linking the arson attacks.

“What we do see is youth are being tasked to carry out these arson attacks, which is very similar to tobacco arsons,” Detective Inspector Murray said.

“We’re seeing them paid a few hundred bucks to a thousand-odd dollars.”

Investigators urged anyone who saw suspicious behaviour near licensed venues, particularly in the early hours, to contact police.