Unifor National President Jerry Dias will attend a solidarity rally next week in Orillia to protest recent job cuts at Casino Rama.
65 full-time unionized employees were let go last month.
That was followed up days later by an undetermined number of non-union jobs being eliminated.
Unifor has launched a #NoJobsNoDice campaign against Casino Rama's operator, Gateway Casinos and Entertainment.
The solidarity rally is taking place August 8 from 11 am to 1 pm at Tudhope Park.