BEIJING (Reuters) - China's ruling Communist Party will hold a crucial meeting in October to map out and revise rules for internal party discipline, state media said on Tuesday, as President Xi Jinping continues to press home a battle on deep-seated graft.

Xi has waged an ambitious campaign against corruption since assuming power almost four years ago, in which dozens of senior officials have been jailed, including the powerful former domestic security chief Zhou Yongkang.

Tuesday's decision followed a meeting of the Politburo, one of the party's elite ruling bodies, chaired by Xi, the Xinhua news agency said.

"In the new situation, generally intra-party political life is good, but for some time now there have appeared some outstanding issues," it said, without identifying the issues.

Xinhua gave no details of what the revised rules for supervision in the party would entail, but cited speakers at the Politburo meeting as saying the time had come to alter them.

Meetings such as the one planned for October are formally called plenums, are typically held annually as the party's most important event of the year and tend to map out major policies for the years ahead.

The October gathering is likely to be the final plenum before the party holds its five-yearly congress, expected some time in the autumn of 2017, where Xi will cement his power and possibly anoint a successor.

The last plenum before the party congress is typically used to discuss ideological issues, and other plenums under Xi have focused on economic matters and the rule of law.

At last year's plenum the party announced a landmark easing of family planning restrictions, to allow all couples to have two children, after decades of a strict one-child policy.

(Reporting by Ben Blanchard; Editing by Clarence Fernandez)