As part of the current EBA section 21.6 Employee must give notice:
The Manager or another appropriate employee must be informed, prior to the commencement of duty, if practicable, of the employee’s inability to attend duty.
In the case of carer’s leave the employee shall, wherever practicable, give Australia Post notice of the leave prior to the absence, the name of the person requiring care and their relationship to the employee, the reasons for taking such leave and the estimated length of absence.
If it is not practicable for the employee to give prior notice of absence, the employee shall notify the employer by telephone of such absence at the first opportunity on the day of absence.
NOTE: It is NOT your responsibility to ring other employees from your facility or other facilitates to arrange cover for your shift whilst you’re on the above mentioned leave.