I would like to add: the Act was amended in 2008. The section of the Act dealing with investigations by the Commissioner was changed at the same time. It now provides that the Commissioner could conduct an investigation if she believed it was necessary to ensure compliance with the Lobbyists' Code of Conduct and the Act. Formerly, before July 2008, the powers of investigation applied only to the Code. The Commissioner's powers were broadened in 2008.
On February 10th, 2011. See this statement in context.