Mystery surrounds the shock absence of Beijing Olympian Mark Jamieson from the Australian team for the world track cycling championships.

A Cycling Australia spokesperson has confirmed that Jamieson stepped down from all national commitments at the end of last month "for personal reasons".

He has returned to his home in Tasmania and has been unavailable for comment.

The 24-year-old was one of Australian cycling's better performers during the disappointing Beijing campaign. He also was part of the teams pursuit squads that won World Cup rounds over the last few months in Melbourne and Beijing.

Only four members of the Beijing Olympics team are in the Australian squad for the worlds. The massive turnover of talent in the track program reflects the ongoing rebuild following the Olympics disaster.

After winning six golds and 10 medals in total at the Athens Games, Australian cycling only managed one silver last year - its worst Olympics return since Moscow in 1980.

The courageous winner of that lone medal, sprinter Anna Meares, will lead the team for the March 25-29 world titles in Pruszkow, Poland.

Retirements, post-Olympic sabbaticals and professional road commitments explain much of the wholesale absence of veteran riders.

Martin Barras is also no longer the head track coach, with Gary West taking over as interim sprint coach.

The oldest member of the team is sprinter Jason Niblett, who turned 26 six days ago. Meares and track endurance rider Belinda Goss are 25, but otherwise this is a squad of babies.

Still, they have undoubted potential. The other three members of the Beijing team, endurance riders Jack Bobridge and Cameron Meyer and team sprint lead-off specialist Daniel Ellis, all have strong futures.

Bobridge's form this summer has been spectacular as he raised eyebrows with a four minutes, 18 seconds individual pursuit time. He also attracted plenty of attention on the road during last month's Tour Down Under, with Lance Armstrong praising the teenager's fighting spirit.

Shane Perkins has dominated sprint events in Australia over the last few months and won four gold medals earlier this month at the national titles.

The 17-rider squad features a "long team" of nine for the track endurance events. They will have a pre-worlds camp in Adelaide before the final team is confirmed by March 12.

"One male and up to two female riders might not progress to the world championships," Cycling Australia announced in a statement. "Selection of the final team will be based on trials, training performances and general assessment by national track coaches during the camp."

Squad: Ashlee Ankudinoff, Jack Bobridge, Rohan Dennis, Tess Downing, Daniel Ellis, Belinda Goss, Leigh Howard, Sarah Kent, Anna Meares, Kaarle McCulloch, Cameron Meyer, Travis Meyer, Jason Niblett, Glenn O'Shea, Shane Perkins, Scott Sunderland, Josephine Tomic.

Roger Vaughan
AAP