THE opening of the Shenzhen office of the Securities Regulatory Commission has added to confusion over responsibilities of securities organisations, to the disadvantage of investors, a Shenzhen Stock Exchange official says. From April 1 the commission took over the roles of several organisations - including the Shenzhen branch of the People's Bank of China - in regulating the securities industry. An official at the Shenzhen branch said then that the roles of the different bodies involved would be clearly identified. However, the Shenzhen exchange official said the lack of well-defined roles created problems for the exchange. ''Authority attribution is not clear. This can be a stumbling block for us,'' he said. ''For instance, when we take action against people, they may accuse us of mishandling the case at another securities organisation.'' Without elaboration he said: ''And inconvenience occurs actually in many other aspects of our job.'' Creation of the commission's Shenzhen branch had blurred roles in an already unclear area, he said, referring to restrictions when the exchange sought to handle complaints which had once been dealt with jointly by the exchange and the Shenzhen branch of the People's Bank of China. ''Now the bank doesn't take care of these any more. And we don't know if the commission is supposed to be in charge,'' he said. ''There are things we want to do but can't do just yet. We first need to know the scope of our responsibilities now.'' Of investors' complaints, he said the majority concerned telephone broking services introduced last year. Such complaints were also on the rise. Investors can now place buying or selling requests with brokers after quoting their own secret codes for identification. Complaints about this service centred on unauthorised transactions and the failure of brokerages to buy or sell for clients. ''As the stock market develops and new services are constantly introduced, unethical brokers are bound to crop up. But investors are also getting conscious of the need to ask,'' the official said. However, he said only a few complaints had been received lately by the exchange about illegal margin loans by securities houses to customers, following an official crackdown. The Shanghai exchange recently fined four houses for making illegal loans to customers.