The US Justice Department has launched a probe into IT giant IBM over alleged anti-competitive behaviour within its mainframe business, according to reports.

The BBC is claiming that The Computer and Communications Industry Association (CCIA) is accusing IBM of withdrawing software licences from business clients who do not also buy its hardware. The CCIA complaints have prompted the Justice Department investigation, according to the report.

“IBM will tell big customers that if you buy that other stuff, we’re not going to let that stuff talk to our stuff, said Ed Black, CEO of CCIA. We think of the Internet as open and innovative, but that’s a lock ’em up and keep ’em locked up strategy. That’s very unsatisfactory for the customer base.”

IBM has denied the claims and said it will cooperate fully with the enquiry.

The CCIA first complained to the Justice Department last month, and the US government department has now started canvassing opinion from IBM’s rivals about the claims.

According to The Associated Press, one company to receive a request for information is T3. The Florida-based firm launched a similar antitrust case against IBM in the EU earlier this year. It is also suing IBM in the US for similar reasons, although that case was dismissed last week.

“We understand the Department of Justice has asked T3 for documents from the litigation, IBM said. We continue to believe there is no merit to T3’s claims, and that IBM is fully entitled to enforce our intellectual property rights and protect the investments that we have made in our technologies.”