More than half of the unaffiliated voters who cast ballots in Sunday's House of Councilors election threw their support behind the Democratic Party of Japan, according to Kyodo News exit polls.

Some 19.2 percent of those who responded to the survey said they don't support a particular party. Of these, 50.8 percent said they either voted for the DPJ or for a DPJ-backed candidate.

This is more than double the percentage of unaffiliated voters who said they voted for the DPJ in the previous Upper House election in 2001. This indicates it was the unaffiliated vote Sunday that propelled the main opposition force past the Liberal Democratic Party.