Prime Minister Shinzo Abe's ruling Liberal Democratic Party has extended its lead over opposition parties, according to a Kyodo News poll, as the campaign for the July 21 Upper House election heats up.

The latest nationwide survey, conducted for two days from Friday, shows support for the LDP has edged up 2.2 percentage points to 31.0 percent from the previous poll conducted on June 26 and 27.

The survey also found that 7.2 percent said they would vote for the main opposition Constitutional Democratic Party of Japan, down 1.8 points.