There's a whole section of offences in the Criminal Code—if I recall, it's section 121—about influence-peddling, bribery, fraud and misconduct by public office holders and officials. There are sanctions put on people trying to bribe politicians and on politicians who accept bribes, just to use one example.
The criminal law is its own world, with very high standards for burden of proof. You're innocent until proven guilty. It has well-established rules of procedure and evidence, which are at a higher bar than the one Parliament has given to the various commissioners and officers of Parliament. Parliament has allowed commissioners to stray into things that are not criminal offences but may be important, so that's why you have the Lobbying Act, the ethics code and the Conflict of Interest Act. The standards for evidence and procedure are quite different from in a criminal court.