The Australian Workers' Union (AWU) has been prevented from investigating a fatal forklift incident at a north Queensland mine.

A man, 19, was killed 350 metres underground after a basket fell from a forklift on December 15, 2006, at BHP Billiton's Cannington Mine, near Mt Isa.

Responding to an AWU written request to investigate the incident, BHP said "we do not believe anything can be usefully added", an AWU statement said.

AWU national president and Queensland secretary Bill Ludwig said the union was unable to gain access to the site, due to WorkChoices legislation that restricted the ability of unions to investigate health and safety risks at workplaces.

"It is now easier for people to visit David Hicks at Guantanamo Bay, than for unions to meet their members in the workplace to make sure they are safe at work," he said.

A Queensland Government Department of Mines & Energy spokesperson would not comment on the union's capacity to investigate the fatality and said the Police and the Mines Inspectorate were investigating.

"It would be inappropriate to comment further at this time. It is important not to prejudice a Police and Mines Inspectorate investigation that will ultimately come before the coroner," he said.

"This is about the tragic loss of a young man's life. It is important to identify what went wrong and to find out not only how it happened, but why it happened."

Ludwig said the AWU would meet Queensland's Mines & Energy Minister Geoff Wilson to discuss "the next steps in forcing BHP to clean up [its] act and look after the safety of workers".

A Queensland Workplace Health & Safety (WHSQ) spokesperson said WHSQ, a division of the Queensland Government's Department of Industrial Relations, did not have jurisdiction for mine safety in Queensland.