In some states in Australia, sick or personal leave should not accrue while an employee is receiving workers compensation payments. See: Fair Work Australia - Annual leave and sick leave during workers compensation for more details.
However, to stop sick or personal leave from accruing while on workers compensation:
Go to Setups, Payroll, Leave Tables, Maintain.
Select the sick or personal Leave Accrual Code.
From the Pay Elements tab, in the Elements of pay to Accrue task area, un-tick Workers Compensation, or un-tick this setting if the leave table has already been created.
Click Accept (F9) to save the change.
See also: Set up a Personal Carer's Leave table.