The swearing-in ceremony was held in the presence of Tamil Nadu chief minister J Jayalalithaa.
On Monday, Jayalalithaa had dropped Agriculture Minister S Damodaran, Revenue Minister B V Ramanaa and Labour Minister K T Pachamal from her Cabinet.
Krishnamoorthy is Minister for Agriculture while Velumani and Indira have been allotted the portfolios of Municipal Administration and Rural Development and Handlooms and Textiles respectively.
Jayalalithaa had also redesignated some of the other Ministers, including K P Munusamy, who had hitherto held the Municipal Administration and Rural Development portfolio. He is now Labour Minister.