THE Planning Department has given four performance pledges to the Hong Kong public, with a self-imposed 85 per cent achievement target. The commitments would further the goal of ''providing an efficient, courteous and professional service'', said Dr Peter Pun Kwok-shing, the director of planning. The pledges focus on four services - general information on planning matters; the processing of development proposals; services related to the work of the Town Planning Board; and the investigation of alleged unauthorised development, especially in the New Territories. For general planning information, the objective is to answer straightforward enquiries immediately, while more complicated verbal enquiries should be answered within three working days. Correspondence would be answered, at least partly, within 10 days, with a three-week deadline for more complex cases. The department would strive to process development proposals promptly, Dr Pun added. On receipt of a proposal, the target would be that a written reply should be issued within three months. However, for proposals that might have a significant impact on other planning, transport or the environment, the permitted response time would be extended. Dr Pun said: ''We will follow the provisions of the Town Planning Ordinance in preparing statutory plans and processing planning applications. ''To further improve the service, applicants or objectors will be informed in writing of the board's decisions within seven working days from the date of the confirmation of minutes of relevant board meetings. ''For straightforward cases, verbal replies can be given after the board meetings, on request,'' he added. Reports from the public of alleged unauthorised development would result in a prompt site inspection, with a reply within four weeks. Dr Pun conceded, however, that he could not promise quick enforcement, because of uncertainties over boundaries and land ownership, together with a staff shortage. Performance would be monitored, and the results published annually.