A series of firebombings have hit Melbourne's suburbs as part of an escalating gang war.

Properties linked to Mohammed Oueida, a significant organised crime figure who spends much of his time in the Middle East, were badly damaged in the fires.

Multiple cars were completely destroyed in the attacks, which took place in suburban streets in Melbourne's outer north.

Sources familiar with the firebombings believe they form part of a troubling new chapter in gang violence related to the drug trade.

Mr Oueida, who survived an assassination attempt last year, escaped the firebombings unscathed, but the two attacks in less than three weeks saw hundreds of thousands of dollars worth of property destroyed.

The firebombings underline that Mr Oueida, a high-priority target of federal authorities, is also being ruthlessly pursued by criminal elements.

A Holden Commodore was also badly damaged in the attack. ( Supplied )

Police believe both threats partially explain his reluctance to spend any significant period of time in Melbourne since he was released from prison in December, 2016.

Taskforce Echo detectives will investigate if the fires represent yet another flashpoint in the battle between factions aligned to Mr Oueida and the Tiba family, who were subject to a grenade attack last November.

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A Mercedes four wheel drive was completely destroyed after a fire attack. ( Supplied )

On July 13, two cars and a garage at a property linked to Mr Oueida in Craigieburn were destroyed in a firebombing attack that caused more than $100,000 damage.

A Thomastown home and BMW linked to Mr Oueida was firebombed in August. ( Supplied )

Photos obtained by the ABC show a Mercedes-Benz ML350 4WD and a Holden Commodore sedan were destroyed in the fire. It appeared the attackers ignited several firebombs, including one against the front door of the suburban home.

Less than three weeks later, a BMW sedan was destroyed and a property in Thomastown badly damaged after the fire spread from the garage into the roof of the house.

A woman had to flee with her daughter and two grandchildren from the house, with the ceiling above a bedroom collapsing soon after they had evacuated. The damage bill is estimated at $200,000, with a neighbouring property also burnt.

At the same time as tensions escalate in the region, police have started putting the squeeze on some of the main players involved in the violence.

'Henchman' ensnared by new police orders

It can be revealed that an alleged henchman for suspected organised crime figure Nabil Maghnie, another enemy of the Tibas, has become the first person in Victoria found with a gun under the state's new firearms prohibition order regime.

Savio Mansour was allegedly found with a gun, ammunition and drugs after a police raid. ( Supplied )

Savio Mansour, 19, was allegedly found with a gun, ammunition, and drugs including methamphetamine, ecstasy and cannabis during a police raid of his Roxburgh Park property on July 13.

The powers were introduced to cut the number of shootings and guns circulating in the underworld.

According to statistics provided by the Victoria Police armed crime squad last year, about two thirds of all non-fatal shootings in the state occur in Melbourne's north-west. The region's troubled recent history of violence is linked to the drug trade.

"These tough new laws … we know they will be a game changer in driving down harm in the community," Police Minister Lisa Neville said when the laws were introduced in February.

Mr Mansour had been served with a firearms prohibitions order only days before his property was searched. Those subject to an order — or in the presence of someone subject to an order — can be searched without a warrant by police.

Mr Maghnie, also known as Nabil Moughnieh, has been shot at least twice, and drove himself to hospital after taking a bullet to the head in 2016.

A police spokeswoman said that 83 firearm prohibition orders were active as of July 31, with senior officers previously stating that suspected extremists, bikie gang members, and Middle Eastern organised crime figures had been targeted.

Firebombings follow grenade attack

Police believe one of the most volatile and prolific underworld feuds in Victoria is the battle between Mohammed Oueida and the Tibas. While these feuds are typically fluid and involve shootings between people who were previously considered allies, this conflict shows no sign of abating.

On November 19 last year, a mother and her infant child were sleeping in the front room of a house in Lalor occupied by members of the Tiba family when an M52 grenade was detonated.

A front window in the house was shattered and two cars parked on the street were significantly damaged in the explosion, but no-one was injured.

Police said at the time they believed the attack "was targeted and is linked to ongoing feuds between a number of Middle Eastern organised crime groups."

It remains unclear whether the grenade was thrown by a person loyal to Mr Oueida, or another enemy of the Tibas.

Mr Oueida was described as "the new [Tony] Mokbel" by a judge after his arrest in 2011.

It was alleged he had $6 million in a Swiss bank account, a light plane, a $2.8 million mansion, a Ferrari, and suspected property and business interests in Lebanon, the Solomon Islands, Abu Dhabi and Pakistan.

Police believe he has wasted little time in returning to business since being released from prison, but may have curtailed his flamboyance in a bid to stay under the radar.

He has been suspected of involvement in at least one significant drug importation since his release, but has not been charged by police.

Mr Oueida was shot in April last year as he left lunchtime prayer at a mosque in Coburg. Two members of the Tiba family have been charged in relation to the shooting.

Mr Oueida has been overseas for most of the time since the attack, predominantly in Lebanon and Dubai — a haunt for a string of Australian organised crime figures.

The city was considered an enclave from Australian authorities until last August, when four men — including two brothers of Sydney identity John Ibrahim — were arrested by United Arab Emirates police and then extradited in relation to an alleged international drug smuggling syndicate.

It was the first successful extradition from the UAE on behalf of Australian authorities, the Australian Federal Police confirmed at the time.