A weekly rest day is important for an employee’s well-being. Your employer can only require you to work on your rest day under exceptional circumstances.
Rest day pay is set at a higher rate to compensate employees for the extra hours worked. Your employer cannot give you time off instead of rest day pay if they ask you to work on a rest day, if you are covered under Part 4 of the Employment Act.
If you are not covered under Part 4, the entitlement would depend on what is in your employment contract.