Any company may, subject to the provisions of section 279, at an annual general meeting by resolution passed by not less than three-fourths of such members entitled to vote as are present in person or by proxy, determine that any person then holding office as its auditor shall not be reappointed or that some other person shall be appointed as the auditor of the company: Provided that where an auditor has reason to believe that in the conduct of the affairs of the company a material irregularity has taken place or is taking place which has caused or is likely to cause financial loss to the company or to any of its members or creditors, and he has made a report thereon in writing to the directors of the company, he may not be removed from office until the provisions of section 26(3)(b) of the Public Accountants' and Auditors' Act, 1951 (Act No. 51 of 1951), have been complied with.