助理城市規劃師主要協助執行以下職務，以及接受在職培訓，以汲取城市規劃方面的經驗： (a) 擬備、修訂及落實全港發展策略，以及法定和非法定地區設計圖； (b) 直接參與或透過管理顧問的工作，從而制訂及修訂規劃標準及指引，以及進行規劃研究、調查及城市設計工作； (c) 審批發展建議及規劃申請，並就不同用途物色發展地點； (d) 根據《城市規劃條例》對違例發展項目採取強制執行行動； (e) 研製及運用地理資訊系統和資訊科技技術，方便公眾參與及作出決策；以及 (f) 就跨境基建設施及地區發展事宜進行研究，並與內地部門保持聯絡。

An Assistant Town Planner is mainly deployed on assisting in the following duties and undertaking on-the-job training with a view to gaining experience in the town planning discipline - (a) preparation, revision and implementation of the territorial development strategies, and statutory and non statutory district plans; (b) formulation and revision of planning standards and guidelines and carrying out planning researches, studies and urban design work either directly or through managing the work of consultants; (c) processing development proposals and planning applications and carrying out site searches for various purposes; (d) undertaking enforcement actions against unauthorised development under the Town Planning Ordinance; (e) development and application of geographic information system and IT technologies to facilitate public participation and decision making; and (f) carrying out research and liaising with Mainland authorities on cross-boundary infrastructure and regional development matters.