Ernst & Young Hong Kong, which resigned as the auditor in 2010 for a Chinese water treatment company planning an initial public offering, doesn't hold the audit papers the city's regulator wants, a court was told.

"The performance of the engagement was carried out by Hua Ming and all the working papers were created by staff of Hua Ming," the audit firm's lawyer, Benjamin Yu, said on Wednesday, referring to its Beijing-based affiliate Ernst & Young Hua Ming.

Hong Kong's Securities and Futures Commission, believes Ernst & Young Hong Kong either possesses or has access to the documents, its lawyer, Jat Sew Tong, told the city's Court of First Instance on Wednesday.