Vice-minister for police, Bui Quoc Huy, and the head of state radio, Tran Mai Hanh, were expelled from the powerful Central Committee, the 150-stong decision-making arm within the party.
A statement from the committee said the men were sacked for "having direct connections during a long period with some bad elements" in a mob headed by underworld kingpin known as Nam Cam.
The dismissals follow a lengthy and wide-ranging investigation into the activities of Nam Cam as part of the government's drive to stamp out corruption.
The BBC's Clare Arthurs in Hanoi says about 80 officials have been arrested as part of the investigation.
It comes at a time of official concern that the Communist Party's grip in power is threatened by growing public anger about corruption.
Political angle
Diplomats said the inquiries into high-level collusion with the gang could be connected to political machinations ahead of a cabinet reshuffle due to be approved by a new National Assembly, which will open its first session on Friday.
The statement from the Central Committee said Mr Huy did not fulfil his previous job as the police chief in Ho Chi Minh City while Nam Cam's gang was active.
Nam Cam's gang
Accused of:
Murder
Drug trafficking
Prostitution
Extortion
"As director of police in Ho Chi Minh City, he allowed the Nam Cam gang to operate unhindered for a long time," it said.
He had allowed staff to become "degenerated" and act as accomplices for the mob headed by Nam Cam, who is now in jail in Ho Chi Minh City charged with offences including murder, drug trafficking, prostitution and extortion.
'Power abused'
Mr Hanh "had abused his power and the press", the statement said.
"Tran Mai Hanh has been purged for publishing articles advocating the early release of Nam Cam," it added.
The party has asked the National Assembly to sack Mr Huy and Mr Hanh from their current posts.
Other senior party officials have been implicated, including a former top prosecutor.
At least 109 people, including another prosecutor and several senior police officers, have been arrested during the inquiry.
The cabinet list decided by the party will be officially approved during the first month-long session of a new 498-member National Assembly, which starts on 19 July.