Lawmakers want the government to clarify its treatment of offshore profits and earnings originating from the mainland. But they have stopped short of advocating a review of the 29-year-old Inland Revenue Ordinance. A motion introduced by legislator Mandy Tam Heung-man had sought a comprehensive review of local tax laws and the creation of a statutory advisory body to conduct a policy study on the ordinance. A watered-down version of the motion seeking simply to 'examine the specific issues' relating to the tax system, as amended by Patrick Lau Sau-shing, was passed by Legco. Liberal Party legislator Jeffrey Lam Kin-fung said Hong Kong taxes on half of the mainland-derived profits from manufacturing and trading were of increasing concern to industry. 'The so-called 50/50 tax plan is unclear and that has caused some concern,' Mr Lam said. A grey area on rules governing exemptions for goods exported overseas has seen the government charge back-tax in a number of cases.