Senegal has authorised the West African country's first oil development, the $US4.2 billion Sangomar offshore oil project, operator Woodside Petroleum has announced.

The government also approved a proposed plan for the exploitation of oil at three offshore joint venture projects – Rufisque Offshore, Sangomar Offshore and Sangomar Deep Offshore, Woodside said on Thursday.

The three offshore projects are joint ventures between Woodside Energy, Cairn Energy PLC, FAR Ltd and Petrosen.