Sinking voter support for Aso has triggered talk among lawmakers in his Liberal Democratic Party (LDP) of replacing him before an election the party looks increasingly likely to lose.

But 30 of 47 party chapter executives surveyed by the Asahi newspaper said Aso should lead the LDP in the next election, although some said they backed him only reluctantly.

Party chapters were instrumental in toppling then-prime minister Yoshiro Mori in 2001 after a plunge in voter ratings, and threw their support behind his successor, Junichiro Koizumi.

Local party officials said there was little hope for a turnaround in the party's fortunes even if Aso stepped down.

Aso became Japan's third prime minister in less than two years after an LDP vote last September with overwhelming support from party chapters.

"We chose him in the party leadership election," an official from the Tokyo chapter was quoted as saying. "Even if we make a fuss now, it'll just weaken our organization."

LDP lawmakers' frustration with Aso swelled further this week when his finance minister resigned after being forced to deny he was drunk at a G7 news conference in Rome.

Aso apologized for the resignation in parliament, where he faced a grilling from the opposition and some harsh words from even a coalition lawmaker.