Some 40 percent of voters recently surveyed by Kyodo News said they support the Liberal Democratic Party, up about 6.4 percentage points from the time of the 2000 general election.
According to the nationwide telephone survey conducted on about 145,000 people between Friday and Saturday, support for the Democratic Party of Japan also rose, by 2.3 percentage points to 11.9 percent. The results were released Monday.
Political observers said this indicates that Sunday's general election for the House of Representatives is shaping up to be a showdown between the nation's two biggest political forces.
The popularity of the LDP recovered substantially in urban areas, as seen in the 8.3 percentage point surge in Tokyo. But the DPJ, which views itself as being stronger in the cities, showed a smaller rise in the Tokyo metropolitan area.
As for the other major parties, support for New Komeito remained virtually flat, edging up just 0.3 percentage point to 4.5 percent. The Japanese Communist Party saw support slip 0.9 percentage point to 3.2 percent, and the Social Democratic Party saw a 1.4 percentage point slide in its support to 2.5 percent.