SYDNEY (AFP) - Commonwealth Games medal hope Isaac Cooper was on Tuesday (July 19) axed from Australia's swim team and sent home over "wellbeing challenges, including the use of medication".

The fast-emerging 18-year-old had been favoured to make the podium in the 50m and 100m backstroke events at the Games in Birmingham starting next week.

He finished eighth in the 50m backstroke at the recent world championships in Budapest and was part of Australia's silver-medal winning mixed medley relay team.

But Swimming Australia said he was on his way home from their training camp in France "following some wellbeing challenges, including the use of medication".

"He has acknowledged his mistakes and accepted the consequences, and Swimming Australia will continue to support him as he addresses these challenges," the governing body said in a statement.

A decade ago, Australian swim team members were embroiled in scandal after some took the sleeping tablet Stilnox, a sedative-hypnotic drug used to treat insomnia, at a bonding session ahead of the London Olympics.

The incident was investigated by the Australian Olympic Committee because it had banned team members, regardless of their discipline, from using the drug.

It culminated with the entire 4x100m men's relay squad - James Magnussen, Tommaso D'Orsogna, Cameron McEvoy, Eamon Sullivan, Matt Targett and James Roberts - being fined and handed deferred suspensions.

It was not known what medication was involved with Cooper, but Australian media reported it was not Stilnox-related.

"The welfare of our athletes remains our absolute priority," Swimming Australia added. "Swimming Australia is vigilant in educating athletes of their obligations under the National Integrity Framework and will continue to provide all necessary support to ensure they uphold the highest standards and behaviours when representing Australia."