The General Secretary of the Communist party, Nguyen Phu Trong, has signalled that more senior officials are being targeted for corruption and maladministration.
He told attendees at a town hall meeting in Hanoi that they should wait to hear about other pending cases, following the dismissal last week of the politburo member, Dinh La Thang.
The party has portrayed the abrupt demotion of Mr Thang as part of a cleanup campaign promised after last year’s party congress.
Dinh La Thang was removed from his post in the politburo and as party boss in Ho Chi Minh City after being accused of “serious errors” during his tenure as head of PetroVietnam more than six years previously.
His reappointment as vice head of the central party’s economic committee body raised questions about the nature of the case against him.
Some suspect his new position will be only temporary while the authorities now investigate criminal charges against him.
Some analysts see his demotion, and moves against other officials, as a symptom of infighting in the leadership.
Mr Thang was closely associated with the former prime minister, Nguyen Tan Dung, who lost out in a power struggle last year to Nguyen Phu Trong, who was reappointed for a further term as general secretary.
Some wonder whether Mr Trong has been inspired by his counterpart in China, Xi Jingping, who has used corruption allegations to eliminate potential opponents.
Mr Trong said that tough measures had been taken and would continue to be taken against officials responsible for mismanagement.
He said that Mr Thang had been dealt with by the party and was now being investigated by the judicial authorities for possible criminal offences.
He dismissed reports on social media that the campaign was part of a political purge.
He said that all cases would be dealt with legally and ethically.
State media say that 125 people have been brought to trial on corruption charges since the beginning of last year.