Australia expects permission to call-up another diver to replace heartbroken Brittany Broben, who has withdrawn from the Rio Olympics because of injury.

But the nation's absence in the blue-riband men's 100m sprint will stretch to at least four Olympiads with Josh Clarke pulling out of the Games because of a hamstring injury.

The 21-year-old Clarke has been hailed for a courageous decision to not compete in Rio because he is not in peak condition after injuring a hamstring tendon in February.

"He has chosen to look to his future rather than focusing on an immediate outcome which is never easy," Australian athletics head coach Craig Hilliard said.

Australia has not had a men's 100m sprinter at an Olympics since 2004 and Australian Olympic team chef de mission Kitty Chiller also praised Clarke's honest decision.

"It's a strong and it's a brave decision from a young guy with a big future," Chiller told reporters in Rio de Janeiro.

"Very disappointing for Australia that we won't now have a 100 metre (runner)."

But Chiller expects Australia to be allowed to replace Broben in the 10m platform event after the London silver medallist withdrew from Rio because of shoulder problems.

Australia's squad is now searching for a replacement for the injured Brittany Broben. ( AAP: Dan Peled )

"We have received a letter from FINA, the international diving federation, that it is likely that we will keep that quota spot," Chiller said.

"So we're currently working with Diving Australia to clarify that with FINA and then obviously work through what the process is with nominating someone else for that quota spot.

"It was a quota spot that was earned for Australia so theoretically one would think that we would keep it."

Australian selectors had used their discretionary powers to pick Broben for her second Games after she suffered a shoulder injury at the Olympic trials in May.

Broben had been plagued by shoulder problems since her 2012 London podium finish, the injury forcing her out of the 2014 Commonwealth Games and last year's world titles.

"Brittany has been fighting hard to return to full fitness and she and Diving Australia were confident she was going to be ready to perform at her best in Rio," Diving Australia chief executive David Bell said.

"Unfortunately this setback has put paid to her chances."

Broben's withdrawal from the nine-strong Australian diving team is a major blow to their hopes of earning a medal at a fifth-straight Olympics.

AAP