Peter Pellegrini, who only recently admitted that he was ready to challenge the only-ever Smer chairman Robert Fico in the next vote for the part's top post, said his departure from Smer could be "one of the solutions".
He will leave if he does not succeed with his candidacy for the chairman post.
Pellegrini served as prime minister after the cabinet reshuffles that followed the Kuciak murder and the ensuing street protests against the Fico government in Slovakia in 2018. He concluded his term on March 21, shortly after the coronavirus outbreak in Slovakia, and is currently the most popular Smer politician in polls.