Former public service commissioner Lynelle Briggs will lead a major inquiry into health and safety laws on Canberra's building sites.
Attorney-General Simon Corbell will announce the appointment of Ms Briggs, who is also a former Medicare chief executive, today to chair the inquiry.
The government will also release today the inquiry's terms of reference which call for an investigation into ''any systemic or cultural behaviours on construction sites'' that might be putting workers in danger.
But there are no plans for the inquiry to hold public hearings.
Mr Corbell announced the planned investigation - in which witnesses' evidence will be protected from defamation, criminal and other legal action - last month in the wake of the fourth workplace death in Canberra since December.
Three of the dead were working in the civil and construction sector, and the fourth man was a painter.
The Attorney-General said too many companies were trading off the safety of their workers on Canberra construction sites for extra profits.
The latest man to die, 21-year-old concreter Ben Catanzariti, was working at a Kingston Foreshore construction site on the morning of Saturday, July 21, when he was struck by a 39 metre boom and died at the scene.
ACT Work Safety Commissioner Mark McCabe will play a supporting role to the inquiry which will have powers under the Work Health and Safety Act to take submissions, call for papers and question witnesses.
''Since December last year there have been four workplace deaths, three of which have been on construction sites, and this is, put simply, four too many,'' Mr Corbell said last night.
''This inquiry is specifically designed to look at issues of health and safety closely as well as where there can be tighter regulation to better protect workers who work in this high risk industry.
''The inquiry will consider issues such as compliance with current laws and regulatory regimes, on-site behavioural or cultural issues; training requirements or participation rates and powers available to WorkSafe ACT and other regulatory bodies.''
The minister said the government had held talks with building with unions and industry groups while developing the inquiry's terms of reference.
''It is important that we take a wide ranging look at this industry and I am pleased that all groups who represent both employers and employees have cooperated during the formation of this inquiry and I look forward to their contributions to it,'' he said.
''The inquiry will engage with a range of employers, workers, occupational health and safety professionals and other industry stakeholders, including the ACT Work Safety Council.
The inquiry panel will report its findings and recommendations to the Attorney-General by November 16.