Osaka Mayor Toru Hashimoto said Wednesday he would quit politics if voters rejected his merger proposal for the city in a referendum likely to be held on May 17.

"At that point, after all the energy, money and effort I've spent these past four or five years in support of the merger plan, I'd have to squarely admit that I had no ability as a politician, although I'd finish out my term, which ends in December," Hashimoto told reporters.

However, the mayor has also said that he was confident there was enough voter support for his plan to merge Osaka's 24 wards into five semi-autonomous zones.

In late December, Komeito's Osaka chapter, which had opposed Hashimoto's attempts to force the merger through, agreed to support a referendum after being pressured by the party's Tokyo headquarters. Komeito and Hashimoto's Osaka Ishin no Kai (One Osaka) local party have a majority of seats in the city assembly. The plan is opposed by all the other parties.