President Mutharika is Minister of defence and Commander-in- Chief of the Malawi Defence Force and The Malawi Police Services.
Vice President Saulos Klaus Chilima will double as Minister responsible for the Civil Service.
Joseph Mwanamvekha, a lawmaker, will head the ministry of Trade and Industry, while Minister of Gender, Children, Disability and Social Welfare is Patricia Anne Kaliati a legislator too.
New Minister of Natural Resources, Energy and Mining is leader of the opposition United Democratic Front (UDF) Atupele Austin Muluzi. He is also an MP.
Former secretary to the Government, Bright Msaka will head ministry of Lands, Housing and Urban Development, with Paul Chibingu (MP) as Minister of Home Affairs, and Trasizio Thom Gowelo (MP) as Minister of Local Government and Rural Development.
There are two deputy ministers who are also lawmakers, Jappie Mhango at the ministry of Defence with Vincent Ghambi named as deputy minister of education, Science and Technology.
Prior to the latest appointments, ten ministers were serving the Mutharika government with nine of those only appointed last week.
They included Goodall Gondwe as minister of finance, economic planning and development, Dr Allan Chiyembekeza as minister of Agriculture ,Dr Emmanuel Fabiano as minister of education, Science and Technology, Francis Lazaro Kasaila as minister of transport and public works, George Chaponda minister of foreign affairs and Kondwani Nankhumwa minister of information, tourism and civic eduction, Dr Jean Alfazema Kalilani as minister of health, Samuel Bason Tembenu minister of justice , Henry Mussa as minister of labour and Grace Obama Chiumia as minister of sports and youth development.
The new cabinet ministers were expected to be sworn in on Monday in Lilongwe, according to a statement from the Office of the President and Cabinet.
Meanwhile, gender activists have expressed disappointment with the appointment of just three female ministers in the Peter Mutharika's 20 member cabinet.