The main opposition Liberal Democratic Party is leading polls a month before Japan's parliamentary election. But many voters are undecided.
The Yomiuri newspaper, Japan's largest, found the LDP had support from 26% of voters while 13% said they backed the ruling Democratic Party of Japan.
Support for two new parties that plan to merge rivalled the DPJ in the survey.
The poll showed that 43% of respondents backed no particular party.
Premier Yoshihiko Noda dissolved parliament and called elections for December 16. The poll was conducted on Friday and Saturday.
LDP led Japan for most of the post-Second World War era. The Yomiuri poll and earlier surveys show it is likely to win the most seats but would have to form a coalition to govern.