ROME (Reuters) - Italian Prime Minister Matteo Renzi suggested on Monday that he may not stay on if a referendum on constitutional reform that he is championing fails.

Asked in a radio interview what he would do if the 'no' vote won in the Dec. 4 referendum, he said: "If I have to stay on in parliament and do what everyone else has done before me, that is, to scrape by and just float there, that does not suit me."

Polls have suggested the 41-year-old prime minister may lose the referendum, which, if the 'yes' vote wins, would reduce the role of the upper house Senate and cut the powers of regional governments.

Earlier this year the premier repeatedly said he would resign in the case of a defeat. More recently, he has declined to confirm that outright, saying discussion of his own future deflected attention from the merits of the reform.

Political commentators have speculated that if he does step down after a 'no' vote, he would then push for early elections in 2017, a year ahead of schedule.

The referendum has also widened divisions in Renzi's Democratic Party (PD).

(Reporting By Philip Pullella)