The Government is seeking to change the law to allow deputy High Court judges to head insider dealing tribunals in an attempt to cope with a rising number of insider dealing cases. Sources said the change was needed as there were more than 12 alleged insider dealing cases under investigation by the Securities and Futures Commission and not enough judges to oversee the cases. Most of the cases occurred last year when many red chips were highly volatile due to asset injection rumours, a source said. Preliminary investigations by the SFC - if it proceeds with the cases - are passed to the financial secretary who can call for a hearing by a tribunal. The source said the Government was planning to set up one more tribunal, giving it three in operation at the same time. A bill gazetted yesterday extended the definition of judge under the Securities (Insider Dealing) Ordinance. The legislation would allow a deputy High Court judge to be appointed as the chairman of an insider dealing tribunal. 'Given the continual growth of Hong Kong's securities market in terms of breadth and depth, the number as well as the complexity of insider dealing cases are expected to increase further,' a spokesman for the Financial Services Bureau said. 'To cope with the increasing work load of the tribunal, the pool of candidates who are eligible for appointment as chairmen to the tribunal must be enlarged.' According to the existing legislation, only a judge or a former judge of the Court of First Instance can be appointed as chairman of an Insider Trading Tribunal. The bill will be introduced into the Legislative Council for approval on September 23.