The phrase "serving minister" refers to someone who currently holds a position as a minister or religious leader and is actively performing their duties in that role. Full definition
Notwithstanding the scathing attacks unleashed on the NPP parliamentary group, Dr. Mahamudu Bawumia, and others who have questioned the direction of our economy, the NPP's assessment of the state of Ghana's economy has been subsequently corroborated by the IMF Staff Report dated May 30, 2014, The World Bank, Standard Chartered Bank, Fitch, Standard and Poors, Moody's and, most recently, by Dr. Kwesi Botchwey, Ghana's longest serving Minister of Finance. (citifmonline.com)
The same goes for serving ministers and advisers to the President, some current NWC and BOT members as well as state executive of PDP. (dailypost.ng)
If you force me to choose between the two ministers, my reluctant vote would go to Mr. Martin, the longer serving minister with the largest drop in interest rates in his term. (remonline.com)