TORONTO - A hearing will be held Monday to determine if a multi-million-dollar lawsuit against CIBC for unpaid overtime can proceed as a class action.

Lawyers estimate the class could consist of tens of thousands of current and former tellers and other front-line workers from retail CIBC branches across Canada.

CIBC has challenged claims that it routinely forces employees to work unpaid overtime, filing affidavits from more than 50 front-line employees who say the bank is a good place to work.

The motion is expected to be heard in a Toronto court over five days and the judge is expected to reserve her decision.

Those involved believe it to be the first major national class action for unpaid overtime to reach the certification stage on a contested basis.

Similar proposed class actions have also been launched against CIBC World Markets and Scotiabank.

The statement of claim in this case alleges that class members are assigned heavier workloads than can be completed within their standard working hours.

It alleges they are required or permitted to work overtime to meet the demands of their jobs and that CIBC fails to pay for the overtime work in direct contravention of the Canadian Labour Code under which they are regulated.