China has appointed Chen Miner, a rising political star, as the Communist Party boss in southwestern Chongqing, cementing his credentials as a contender to join the seven-member Politburo Standing Committee at the 19th Party Congress this fall.

The elevation of Chen, a trusted confidant of President Xi Jinping, is a sign of Xi flexing his political muscle ahead of the leadership shuffle later this year.

Chen previously worked under Xi in Zhejiang province, where Xi was then provincial party leader, and has since ridden on the coattails of his former boss, being elevated rapidly through the party ranks.

In 2012, Chen was made Guizhou deputy party secretary. Less than a year later, and within roughly a month of Xi becoming president, he was promoted to governor, before moving up once more to his current role as Guizhou party boss in 2015.

Sources with ties to the leadership had said Chen could jump straight into the leading Politburo Standing Committee (PSC) with President Xi's support behind him, potentially easing out contenders from rival factions.

The PSC is ostensibly chosen by a vote, but results are typically preordained through an opaque process of horse-trading between the president, outgoing standing committee members, and party elders who remain influential.

Chen is currently only a member of the 205-member Central Committee, and an elevation to the PSC, which has ultimate power over the world's second-largest economy, would involve a two-step promotion, skipping over the 25-member Politburo.

Chen will take over the Chongqing role from Sun Zhengcai, Xinhua said. Sun was seen as another potential candidate to be elevated to the PSC.