Ip (pictured) said while the audit of Cheung Kong was relatively straightforward, the work at Hutchison was more complex.

'Considering the substantial asset base of Hutchison Whampoa as well as the significant scale and diversity of its global businesses which span 53 countries, appointing PricewaterhouseCoopers for Cheung Kong would be the logical choice,' he said.

The proposal to appoint PwC will need the approval of shareholders at the annual general meeting on May 25.

Kwan Wong Tan & Fong, which merged with Deloitte in 1997, has audited Cheung Kong for four decades.

Ip said changing an auditor was 'a big issue', but because of regulatory demands it had to implement the change.

'For the past couple of years, the stock exchange and shareholders wanted us to report financial results as soon as possible. As the accounting principles and standards applicable to Cheung Kong and Hutchison Whampoa have become increasingly complex in recent years ... we have decided that Cheung Kong and Hutchison Whampoa should use the same auditor,' he said.

Hutchison is a major contributor to Cheung Kong's profits.

Deloitte is also the auditor of Sun Hung Kai Properties, whose joint chairmen were recently arrested by the Independent Commission Against Corruption. They are out on bail and have not been charged with any offence.

Ip stressed that Cheung Kong was happy with Deloitte's services, and the accountant would continue to act as auditor for other group-related companies including Cheung Kong Infrastructure, CK Life Sciences, Hui Xian Reit, Fortune Reit and Prosperity Reit.

Deloitte yesterday declined to comment on the change.