The Communist Party of China (CPC) should avoid complacency and be aware of its weaknesses despite increasing praise from the people, Chinese President Xi Jinping said on Monday, a day before the CPC's 93rd birthday.

"Ninety-three years on, our party has united people of all ethnic groups to go through battles, achieve great success in revolution, development and reform and has changed the fate of the Chinese nation," Xi said during a meeting on improvements to the work style and morality of CPC members.

Xi called for "sobriety" in assessing the state of the Party.

CPC members should have be ready for the unexpected and be well prepared for dangers in times of safety, he urged.

The president asked them to understand the "severe dangers" the Party is facing, such as isolation from the people and corruption.

"We must insist on governing the party in a strict manner," he said.

He also extended greetings to all CPC members and staff on the fall of the party's birthday on July 1.

On Monday, the CPC expelled four heavyweight officials, including Xu Caihou, former vice chairman of China's Central Military Commission.

Xu was cited for bribery and may face prosecution as his case has been forwarded by the discipline agency to prosecutors.

The work style and morality of CPC members matters to the survival of the party, Xi told the meeting.

He urged authorities to strengthen implementation of the "mass-line" campaign and ensure its effectiveness.

The mass-line campaign was launched last June to cement Party-people ties and clean up undesirable work styles such as bureaucracy and extravagance.

Xi noted that implementation of the campaign is a long-term and regular task, and efforts must be made to keep undesirable work styles from returning.

To improve Party building, officials in high office should take the lead in creating a sound political environment, he believes.

All officials should act with integrity, telling the truth to their superiors and subordinate and daring to fight bad practice, Xi urged.

"Officials at all levels must keep clean, use their power in the right way and be able to withstand temptation."