BEIJING — China’s national legislature expelled 45 deputies representing the northeastern province of Liaoning over allegations of electoral fraud on Tuesday, in the latest effort to root out corruption and the buying of offices within the country’s authoritarian one-party system.

No details were given of the action taken at an extraordinary session of the National People’s Congress Standing Committee, which normally meets bimonthly.

The move followed an announcement last week that the former vice head of the Liaoning provincial legislature was under investigation on suspicion of taking bribes and committing other illegal acts related to elections.

The state prosecutor announced Thursday that it had taken legal action against the official, Zheng Yuzhuo, who will likely face formal charges and a trial. The province’s former Communist Party chief, Wang Min, was also taken into custody in August and expelled from the party on suspicion of having taken bribes.

Members of the rubberstamp national legislature are nominally elected from provincial, county and township bodies, although the process is highly opaque and exceptions are common. Although the roughly 3,000-member body only meets once a year for about two weeks, membership bestows considerable authority and access to inside information on government policies and projects.

The head of the legislature, Zhang Dejiang, pledged in 2014 to strengthen the body’s oversight of elections when speaking out against an earlier case of vote buying in the central province of Hunan.

Chinese President Xi Jinping has pursued a sweeping campaign against corruption and waste at all levels, although its effectiveness is difficult to gauge due to the lack of a free press or supervision by bodies independent of the ruling Communist Party.