Police have named him as Darren Lee Wilson (26), of New Brighton.
The incident began about midday when an unmarked police car was travelling away from New Brighton on Hawke St.
The motorcyclist rode past the unmarked police car at speed and on seeing the car accelerated towards Marine Parade.
The two officers then saw him travel through a stop sign at speed, police said.
They made a U-turn and activated their lights and siren and had just reached the intersection with Marine Parade when they saw the motorcyclist, about 150-250m further down the road, crash into a vehicle travelling in the same direction but turning right into a carpark.
The red Nissan, with two elderly occupants who received minor injuries, had indicated to turn right into the car-park of New Brighton Surf Lifesaving Club.
As they were turning in, the rider hit their vehicle and was thrown some 10m, police said.
The male motorcyclist, in his 20s, died at the scene.
Friends came to the scene after the crash today. One was seen being taken to the rear of a black hearse by a police officer, where he identified the body.
The man won't be named until police have informed next of kin.
One man, who did not wish to be identified, said he heard the loud "thump" of the crash.
He rushed from the surf club car-park to see the aftermath of the scene. He was shaken up by what he saw, and was surprised that there was not more damage to the bike.
Kathryn Baker, 67, was in her garage when she heard a siren followed by a loud "bang".
"By the time I got out the door, the car was there and the bike was lying a bit up the road with a guy lying on the pavement."
Another witness, who heard the crash, said the man was lying motionless with his body on the footpath and feet on the road.
Two uniformed police officers were giving CPR, witnesses say.
Dennis Baker said the rider "must've flown over top of the car".
"The police officers said he was alive, that his heart was beating," the 72-year old said.
"I thought that was OK, but later we heard he had died. I was shocked."
The Bakers said the occupants of the car looked shaken but otherwise all right. Other neighbours brought them chairs to sit on.
Mrs Baker was saddened by the loss of life.
"All because he went through a stop sign eh. Foolish."
A flatbed truck with a crane removed the bike and car from the scene about 3pm.
The bike smashed directly into the driver's door, causing significant damage and smashing the front windscreen.
Firefighters swept glass off the road before the cordon was lifted.
Friends at Keppel St refused to comment, asking for privacy.
One man said he was carrying the dead biker's young son and asked to be left alone to grieve.
Others were in tears and being consoled.
Police were speaking to witnesses and investigating the cause of the crash as well as carrying out a review of the actions of the police officers involved.
"On the face of the information before me at the moment, I am satisfied where we are at the moment but we need a lot more information to come forward," said Superintendent Andy McGregor at the scene.
It was not yet known how fast he was going, but Mr McGregor said witnesses said he was "travelling very quickly".
"The fact is this person was speeding, breaking the law. If the rider had actually stopped he'd be alive today," he said.
"We are speaking to a lot of witnesses at the moment to ascertain what exactly happened."
The police officers involved are "very upset and shaken up".
