Slain Coconut Cartel leader Lorenzo Lemalu has been farewelled amid a heavy police presence in Sydney's south-west after a proposed memorial venue was shot up a day earlier.

Family and friends gathered at Lakemba Mosque on Sunday morning to pay their respects to the 24-year-old former associate of the Alameddine crime family, who was shot dead in Vietnam last month.

Some mourners wore badges with a picture of Lemalu and the words 'forever in our hearts' as they mingled outside the mosque before his coffin was driven to Leppington cemetery. 

Lemalu's wake was to be held at a function centre at nearby Punchbowl on Saturday afternoon but that was shot up after the event had been cancelled.

The wake had been advertised to take place at Diamond Venues, where a gunman opened fire on the building with an assault rifle. 

Footage filmed by an accomplice of the shooter showed a hooded man in an SUV wielding an AK-47-style rifle as he fired up to 30 shots.

'This window right here cuz. Keep going cuz, keep going. Hold it. Hold it. You done? Let's f**n go lad aha,' the accomplice instructed the gunman, before the SUV sped off.

Ahmad Hraichie, who is widely known as The Muslim Undertaker, referred to Saturday's brazen shooting in several posts on Facebook.

'Today we've got the funeral for our brother Lorenzo who was shot dead in Vietnam,' he said.

'I've never been nervous about a funeral, doing this for so many times. But after what happened yesterday with the shooting at Punchbowl, sometimes you think to yourself and you worry but you know that Allah is the protector.

'As I'm about to get into the mosque here I can see already the [Operations Support Group], the Riot Squad, the police are all lined up, banked up here.'

Mr Hraichie hoped 'all goes smoothly today and that we end up going home back to our families in peace'.

NSW Police were called to Diamond Venues on Canterbury Road at 2.20pm on Saturday, shortly after the shooting. No injuries were reported.

An abandoned SUV was found engulfed in flames a short time later, 4km away in Gillian Place.

Detectives established crime scenes at both locations as an investigation was launched.

'Initial inquiries indicate they are linked,' a police spokesman told Daily Mail.

Photos of the cordoned-off function centre showed several windows peppered with bullet holes and spent cartridge casings strewn across the car park.

The brazen shooting in broad daylight shocked locals.

'I was on the phone to my mate and pretty much told him, I think I just heard gunshots,' one bystander told Seven News.

Another added: 'Obviously scary. I immediately was like to my mum, I think we should move houses.'

In another Facebook post Mr Hraichie wrote: 'We ask Allah to bring peace into this world.'

'It is heartbreaking to see violence, hatred, and bloodshed happening in our own backyard. Lives are being lost, families are being torn apart, and communities are left grieving. 

'As I prepare today to lay our brother Lorenzo to rest, I can't help but reflect on how fragile this life truly is.

'This morning, I woke up very early thinking to myself, what does this day have in store for us? None of us know what awaits us when we leave our homes. None of us know when our final day will come.

'My brothers and sisters, this world is temporary. It is short. The grudges we hold, the hatred we carry, the anger that consumes us - none of it is worth it.'

Lemalu's body was returned to Australia last week, a fortnight after the underworld figure was executed outside a restaurant in Ho Chi Minh City on May 21.

Fellow Coconut Cartel associate Sam Sauni, 27, from Sydney's south-west, was seriously injured but survived.

Two Samoan nationals arrested over the shooting allegedly acted 'under the direction of an individual abroad'.

Steve Tafia and Vaa Vaa were tracked near the Vietnam-Cambodia border on May 25 and taken into custody.

Vietnamese police allege the pair flew into Ho Chi Minh City's Tan Son Nhat international airport on May 14 and 'studied the modus operandi' of their targets. 

Authorities claimed the men 'initially confessed to all their criminal acts'.

CCTV captured Lemalu's final moments standing with a group on a footpath along a busy dining strip before he was gunned down at point-blank range in front of shocked diners.

The Vietnamese Ministry of Public Security said on May 26: 'Currently, law enforcement agencies are focusing on investigating, verifying, and strictly handling the individuals involved in accordance with the law.'

Lemalu was a former member of Proper 60, a western Sydney-based gang linked to the Alameddines led by Ali Younes, aka Ay Huncho, and had the group's name tattooed across his stomach.

It is understood Lemalu fell out with the Alameddines some time after fleeing Australia four years ago and began directing the Coconut Cartel's activities from South-East Asia.

The Coconut Cartel is a breakaway gang locked in an underworld crime feud with the Alameddines over control of the Sydney drug scene.

The deadly shooting has sparked various theories over who was responsible.

Messages obtained by SCN Worldstar and reportedly sent by members of the Alameddine network suggest they claimed credit for the execution.

'That's what happens when Coconuts try (and) fight the people that made them,' a message read.

But not everyone believes the execution is linked with the Sydney gangland wars, in the wake of a series of firebombings and drive-by shootings across the city in recent months.

'The big rumour is they ripped off some Albanians and that's why he was killed,' a gangster living overseas told the Daily Telegraph.

The Coconut Cartel has claimed online that the shooting was a case of mistaken identity.

'Let's clear up the air; this was not an attack from almo claiming it,' a post read. 'It was an accident... Coconut Cartel here and we're still coming for you forever strong.'