China's Communist Party will wrap up a meeting on Thursday that is set to culminate with a resolution that consolidates President Xi Jinping's authority, a year before he is expected to secure a precedent-breaking third term as party leader.

The sixth plenum of the central committee, a group of some 370 party members that chooses its new leaders every five years, has been meeting since Monday behind closed doors in Beijing, accompanied by a drumbeat of state media propaganda.

The "historical resolution", only the party's third since its founding in 1921, is officially about its achievements over 100 years but will also uphold the authority of Xi as the party's "core," further reinforcing his grip on power and laying the ground for what analysts widely expect to be a third term a year from now.