"He (Siddaramaiah) is a mean chief minister," Mr Gowda said while complaining that he was not given an opportunity to speak during the inauguration of Mahamastakabhisheka of Lord Gommateshwara Bahubali at Shravanabelagola on February 7, which was attended by President Ram Nath Kovind.
Stating that his name was printed on the invitation as former prime minister and chief minister and as Lok Sabha member and speaker at the event for "namesake", he said "but I had no chance to speak".
"Is he a chief minister? How long will you stay? I will see. I have taken a vow. I will today seek apology from the people of Karnataka for grooming such an immoral politician," he said.
"Grooming such a lowly chief minister is my biggest mistake. I will repeatedly say he is unfit to continue in the post," a visibly upset Gowda remarked at a party event.
Relations between Mr Gowda and his one-time trusted aide Mr Siddaramaiah came under strain in 2005 as the latter was unhappy over party affairs and dominance of the former Prime Minister's son H D Kumaraswamy, the then JD(S) state unit working president.