The Audi driver who crashed and killed two people in a tragic road smash on Saturday has been branded a 'murderer, maniac and scumbag' - while his mates remember him as a 'true legend'.

Tamati Gilbert, 42, has been lauded as an 'awesome' man with a 'heartwarming soul' on one grieving relative's Facebook page.

But angry Aussies have hit back at the tributes and blasted: 'He's going to hell. Rot in hell Tamati. Scumbag murdered two innocents.'

They branded Gilbert a 'murderer' after he sped off in his high-powered white Audi S4 when police arrived at his home in Sydney's south to conduct a mental health welfare check.

Moments later, the car ploughed into a concrete barrier at high speed on Rocky Point Rd at San Souci. It flipped and became airborne before landing on a blue Toyota Camry.

Uber driver Shoaib Hussain, 22, and his passenger Seamus Duignan, who was on his way home from a concert on his 28th birthday, died at the scene, along with Gilbert.

Police had at no time pursued Gilbert in his vehicle, instead being called to the crash after bystanders reported the accident.

As some showed their sympathy to Gilbert's relative Rawhiti Gilbert on social media, one posted: 'What about the two people he killed?'

'Not one single bit of remorse or care regarding the two people he killed.' 

Another added: 'You're f***ing kidding, aren't you? This c*** killed others through his own reckless endangerment. The c*** deserves no praise.'

One person said it was especially sad that 'he killed two innocent people driving like a maniac running from cops who weren’t even after him'.

The backlash contrasted with the friends and family reaching out to Gilbert's family who described him as 'such a beautiful soul, with a warm smile and a heart of gold'.

One added that he 'was always a laugh to be around'.

The incident began in the early hours of Saturday morning when Gilbert's partner called police to their Gymea Bay house over her concerns for his mental health.

When officers arrived at 12.25am, Gilbert was sitting in his white Audi in the driveway but he took off when police tried to speak with him.

Shortly after fleeing his home, he was caught on CCTV driving at 'considerable speed' before his Audi became airborne at the north end of the Captain Cook bridge.

It crashed over into the oncoming lane and slammed into Mr Hussain's vehicle, killing both him and his rideshare passenger.

Mr Hussain, a social work student who started driving Ubers to help send money back to his family in Pakistan, had just told his best friend that he would be going home after dropping off Mr Duignan.

'He was a kind and nice person, and he was still only young,' Qasim Malik told the Daily Mail. 'His family in Pakistan is completely broken. 

'He came here when he was 18 and hasn't been back since. It is a very big loss for his friends and family.'

Sean Duignan described his brother Seamus as 'a good man, brother and uncle' who was 'never in trouble, just a good man who loved a laugh'.

The NSW State Coroner will investigate the triple fatality.

Mr Malik said Mr Hussain's family wanted his body sent back to Pakistan once the state's forensic medicine facility Lidcombe had finished its examination.

Mr Duignan's mother, Kim Duignan, has demanded a comprehensive investigation into the crash that claimed her son's life.

'There needs to be a complete inquest into what caused this crash,' she said.

Among the tributes posted for Gilbert, one woman wrote, 'I am devastated and shocked by the passing of one of my dearest friends. 

'It was an absolute honour to have you in my life for the last 17 years. I am heartbroken.' 

One of those critical of Gilbert posted: 'My heart goes out to the two innocent people he killed in such a careless act.'

Another said: 'Shame it wasn't just him.'