TOKYO — Voters helped Prime Minister Shinzo Abe of Japan move closer on Sunday to securing the lawmaker support he needs to revise a pacifist Constitution that has been in place since American occupiers created it in 1947.

An official count on Monday morning showed the governing coalition and its allies had captured two-thirds of the seats in the upper house of Parliament, the amount required to proceed with the constitutional revision.

Despite a weak economy and divided public opinion on the expanded role for Japan’s military that Mr. Abe is seeking, his Liberal Democrats and their allies again won a commanding majority in the upper house.

“This is the people’s voice letting us firmly move forward,” Mr. Abe said. When asked whether he would proceed with a revision of the Constitution, he said it had long been the Liberal Democrats’ goal.