Two crashes have marred the last session of the Australian track cycling championships at the Adelaide Superdrome.

Former junior world champion Kial Stewart is in hospital with an injured left shoulder after a two-rider crash during the second round of the men's open keirin.

Queenslander Loren Rowney was forced to withdraw from the women's under-19 20km points race following a crash that brought down more than half the field.

Only six of the 15 points riders were still on their bikes following the crash on the first bend, just after halfway.

The race was able to restart after a few minutes, with Downey in the hands of medical personnel.

Meanwhile in the second round of the keirin, defending keirin champion Joel Leonard of Victoria was relegated and fined $200 for causing the crash that brought down Stewart.

Racing was held up for about half an hour as 22-year-old Stewart, from the ACT, was treated trackside for damage to his left shoulder.

He was stretchered off the track wearing a neck brace and ACT officials declined to give details of his injuries.

The riders were coming off the back straight, about to receive the bell for the final lap, when Leonard crowded American Bart Barczewski down the track.

Barczewski crashed and his bike flew up the track, causing Stewart to also fall.

"We looked at the video footage, there was no point in appealing," Victorian coach John Beasley said of the decision to penalise Leonard.

"It was just one of those blood-rush moments, it's no-one's fault, he just didn't leave enough room for the American."

Leonard finished the race among the top three finishers, but he was soon relegated because of the crash.

Olympic keirin champion Ryan Bayley was among the qualifiers for the men's keirin final, while star sisters Kerrie and Anna Meares made the women's keirin final.

Points race winner Tess Downing was also involved in the crash and she was taken to hospital for observation.

Downing landed on her head in the crash, but was able to take out two intermediate sprints once the race restarted.

While her condition is understood not to be serious, Victorian officials became concerned about Downing's health after the race.

This was Downing's third gold medal of the championships.

The drama continued in the men's keirin final when winner Ben Kersten and second-placed Shane Perkins were initially disqualified.

They successfully appealed the judge's decision, giving Kersten his fourth gold medal of the championships.

The two Commonwealth Games selections were relegated for an incident early in the incident-packed race, much to the fury of the riders and their team support staff.

Kersten also nearly crashed in the closing stages of the race.

Malaysian Josiah Ng was initially declared the winner, while Olympic champion Ryan Bayley won the Australian championship with his second-placed finish.

There was no such controversy in the women's keirin final as Kerrie Meares won her second gold medal of these championships.

Kerrie overhauled sister Anna and American Jennie Reed on the home straight to win her first Australian senior title in the keirin.

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