China's corruption watchdog is investigating a former vice-minister of the aviation regulator for disciplinary violations, saying he had paid below market price for property during his tenure.

The official concerned, Xia Xinghua, who had worked in the Civil Aviation Administration of China (CAAC) from 2009 to 2014, has been expelled from the ruling Communist Party, the Central Commission for Discipline Inspection (CCDI) said on Tuesday.

Xia, who often represented the CAAC in meeting with foreign executives and regulators, also took holidays in the guise of work trips and played illegally in golf games others had paid for, the watchdog said.

"As a leading party cadre, Xia had a weak concept of discipline and violated party regulations," it said in a statement on its website, employing the usual euphemism for graft.

Xia went on to become the chairman of the China Civil Airports Association (CCAA), which represents more than 100 airports, in April 2014, after leaving the aviation regulator, the airport body says on its website.

An official of the airport body declined to comment, and officials of the aviation regulator did not respond to telephone calls. Reuters was unable to reach Xia for comment.

China's far-reaching crackdown on graft has swept through several industries and led to the arrest and jailing of senior politicians and executives. In 2015, the watchdog announced a probe into the deputy head of the aviation regulator.

The fight against corruption has gained "crushing momentum," the Communist Party said last month.