合約海事主任的主要職責是 (a) 監控和規管港口、船舶事務、本地船隻、公眾貨物裝卸區和客運碼頭，並協調區內搜救行動； (b) 主持本地船長合格證書考試； (c) 管理政府船隊運作和海事分處； (d) 進行港口策劃及發展工作； (e) 培訓海事處人員和其他人員； (f) 對付海上污染；以及 (g) 提供海港繫泊服務和海圖製作服務等。 (註： 或須輪班當值、上班候命工作及執行緊急現場職務。）

A Contract Marine Officer is mainly deployed on (a) controlling and regulating ports, shipping and local craft, public cargo working areas and ferry terminals, co-ordinating search and rescue operations in the region; (b) examining candidates for local certificates of competency as masters; (c) managing Government fleet operations and district marine offices; (d) planning the development of the port; (e) training Marine Department officers and others; (f) combating marine pollution; and (g) providing harbour mooring services and hydrographic charting services. (Remarks: May be required to work shifts, or undertake stand-by duties and to attend emergency on-scene duties.)