If your employment contract contains an obligation on the part of your employer to pay overtime pay for overtime work, and you are dismissed without proper notice, your damages would properly include an amount to compensate you for overtime you would have worked. To establish a contractual right to overtime pay, which would be enforceable in a court action, you must show an agreement between yourself and your employer that you would be paid for overtime at overtime rates. This could be an express agreement (either written or simply made by discussion) or it may be established by an actual practice that was followed prior to your dismissal. Also, you will need to prove that if the employer did give you proper notice, your overtime work would have continued.
A recent decision of our Court of Appeal makes clear that statutory overtime cannot be claimed in Court for time worked, though it can be pursued at the Employment Standards Branch. The same decision leaves at large the issue of overtime that would have been worked during a working notice period which was wrongfully denied.