TOKYO (AP) — A battle between rival blocs in Japan’s ruling party escalated Monday ahead of a tax hike vote that is threatening to split the party and weaken Prime Minister Yoshihiko Noda’s hold on power.

The legislation expected to come before Parliament on Tuesday includes a doubling of the current 5 percent sales tax. Noda says it is needed to fight Japan’s swelling national debt, but the political maneuvering has overshadowed economic debate on the bill.