The Prime Minister's Office is the third largest ministry in government. It employs a staff of approximately 550 people in various expert and service positions. It is a key duty of the Prime Minister's Office to support the Prime Minister and the Finnish Government in decision making and in preparing matters in the PMO's purview.

The PMO offers a vantage point to key functions in government decision making, especially in duties relating to the implementation of the government programme, coordination of EU affairs in Finland and state ownership steering policy. It also provides all ministries with joint services relating to translation, languages, ICT, information systems, information management and publications. It is responsible for in-house services, premises and transport services of all ministries.

In addition, the Prime Minister's Office steers, coordinates and develops common administrative and specialist services of the government and its ministries.