Campaigning kicked off in Miyagi and Fukuoka prefectures Tuesday for two House of Representatives by-elections expected to be pivotal in deciding the fate of Prime Minister Junichiro Koizumi's postal privatization drive.

The two polls, which will be held April 24, will also be a litmus test for July's Tokyo Metropolitan Assembly election.

The by-elections involve seats for the Fukuoka No. 2 and Miyagi No. 2 constituencies, which were vacated by members of the Democratic Party of Japan.