A state funeral is being held for the man known as Peter Perfect at St Paul's Cathedral at 11am (AEST).
Sporting luminaries and politicians will join the Brock family inside the cathedral, with thousands more expected to pack Federation Square to watch a live broadcast of the service.
A new Holden VZ Statesman hearse adorned with BROCKY number plates provided by a fan will travel down Flinders St just before 11am, escorted by six police motorcycle riders.
The Brock family, which will include Peter's former partner Bev Brock and new partner Julie Bamford, will follow in a fleet of 12 new Holdens to St Paul's.
Fans will be able to say their goodbyes to the nine-times Bathurst winner by lining Flinders St east of the cathedral.
Brock was killed when the car he was driving hit a tree during the Targa West rally near Perth on September 8.
The funeral service will run for about 90 minutes.
Federal MP Fran Bailey will begin the tributes. She will be followed by Collingwood great Peter Daicos and racing caller Neil Crompton.
A didgeridoo will play a tribute to the "king of the mountain" and Brock's close friend Dr Eric Dowker will also speak at the service.
Daughter Alexandra Brock will pay tribute on behalf of the family and brother Neil Brock will read scripture.
The Dean of St Paul's, the Very Reverend David Richardson, will read a sermon and the hymn Abide With Me will bring the memorial to a close.
Premier Steve Bracks, Lord Mayor John So and Federal Opposition Leader Kim Beazley will attend the funeral.
They will be joined by champion touring car drivers Craig Lowndes, Dick Johnston, Larry Perkins, Allan Moffat and Russell Ingall.
Other sporting greats will include swimmer Grant Hackett and basketballer Andrew Gaze, British Open golf winner Ian Baker-Finch and marathon runner Steve Moneghetti.
Liberal leader Ted Baillieu is sending Education spokesman Martin Dixon to represent him. Federal Sports Minister Rod Kemp will represent Prime Minister John Howard.
Son James Brock said he would carry the casket and Brock's daughter, Alexandra, would carry the state wreath.
The racing champion's body will be carried to the cathedral in a simple coffin with one of his helmets on top of an Australian flag.
The service will be shown live by channels Seven, Nine and the ABC.
James said he was overwhelmed by the show of public support. "Obviously it's just overwhelming. We never expected this much support from all the public. It has been just lovely," he said.
The support of fans had helped the family get through the tough time.