According to home affairs website .....
Employment references must meet the following requirements:
be written on the official letterhead of the company or government department providing the reference;
the letterhead should indicate clearly the full address of the company and any telephone, fax numbers, e-mail and website addresses;
the name and position of the person authorised to sign the employment reference should be typed or stamped below that person’s signature;
the contact telephone number of the person writing the reference should be included in the letter;
the letter should indicate the exact period of employment (including whether permanent or temporary, full or part-time) and the salary earned.