The U.S. Justice Department's decision to hand over documents to a Senate committee of their investigation into the illegal sale and use of steroids among top athletes has been welcomed by a lawyer representing triple Olympic champion Marion Jones.

Jones is one of several top athletes who testified last year before a federal grand jury investigating the Bay Area Laboratory Co-Operative (BALCO), which is at the centre of a steroid scandal. She has denied taking performance enhancing substances.

"This news is great, transparency is our friend in this matter," said Jones's lawyer Joseph Burton in a statement on Tuesday. "Nothing in her testimony provides a basis for USADA (United States Anti-Doping Agency) to take action against her.

"In fact, her sworn testimony confirms what she has said all along that she is drug-free."

The documents handed over by the Justice Department were in response to a subpoena issued this month by the Senate Commerce Committee, which is probing whether U.S. Olympic athletes are using banned performance-enhancing drugs.

Sen. John McCain, an Arizona Republican and chairman of the committee, wants to know if and to what extent Olympic athletes are using banned substances that are difficult to detect by current drug testing methods.

Justice Department spokeswoman Monica Goodling had few details of what was provided to the committee, saying only that it included documents that were produced as part of the government's investigation into the use of steroids in sport.

The subpoena sought information on any purchase from BALCO by Olympic athletes.

McCain, who has been outspoken in efforts to require Major League Baseball to toughen its drug-testing policy, convinced other senators in the committee to issue a subpoena because negotiations with the Justice Department for access to the documents failed to produce anything.

The decision to hand over the documents was also welcomed by World Anti-Doping Agency (WADA) head Dick Pound.

"I think the people in the States are acknowledging the U.S. has a problem and not just the rest of the world," said Pound from his offices in Montreal. "They're trying to push it along as quickly as they can.

"There is a lot of concern, the American public they don't want to be sending athletes to Athens who get bounced."

Four men, including the personal trainer for San Francisco Giants outfielder Barry Bonds, have been indicted by a federal grand jury on conspiracy charges linked to illegal steroids.