Olympic shooting gold medalist Russell Mark says the Australian Olympic Committee's decision to ban athletes from using strong sleeping pills in the lead up to the London Games will cost medals.

AOC President John Coates said Tuesday that Australian athletes will be banned from using insomnia treatments in London, after champion swimmer Grant Hackett revealed he became dependent on sleeping pills during his career.

Mark said in a radio interview Wednesday "if this (ban) happens, it will affect the amount of medals the team wins."

He said he had used sleeping pills for 20 years to ensure he overcame jetlag in the lead up to competitions.