As leave is managed in MicrOpay, an employee record needs to exist in MicrOpay in order for leave balances to appear in ESS. Without leave balances the user cannot apply for leave. A non-payroll user has no record linked to payroll; therefore, there are no options to see leave balances or enter leave applications.
In addition, the leave type needs to be attached to the employee record in MicrOpay. For example, if an employee's record in MicrOpay only has Long Service Leave attached, then this will be the only leave displayed in ESS.