The rules that regulate retired government officials are likely to be tightened amid the country's enhanced anti-graft campaign, analysts said.

The Organization Department of the Communist Party of China Central Committee reiterated on Tuesday that retired officials may not violate Party rules by being employed as independent board members in companies.

All retired officials, including those who hold jobs at universities or NGOs, are prohibited from getting part-time jobs at companies, an official from the department told Xinhua News Agency.

In October, the department issued a regulation that government officials who have retired for less than three years are not allowed to get jobs in companies whose business is related to the officials' former administrative duties.

Even after more than three years of retirement, if former officials want to get jobs at such companies, they must get the approval of the government department where they used to work, the regulation states.

According to the department, as of Tuesday, more than 40,700 incumbent and retired officials, including 229 senior provincial-level leaders, have been required to quit their part-time jobs at companies.

The department did not elaborate on how many of these were retired officials. A report by stock market portal iFinD said that as of April 21, there were 41 retired officials employed by China's top 100 listed companies.

For example, Liu Hongru, 82, former vice-president of China's central bank, was employed with an annual compensation of 243,000 yuan ($39,000) as an independent board member of China National Petroleum Corp, the country's leading gas and oil producer and supplier.

Wang Yukai, a professor of public administration at the Chinese Academy of Governance, said that the companies always pay the retired officials high salaries, and in return, the former leaders are likely to seek profits for the companies with their influence.

Hiring retired officials could destroy fair competition in the market, and such practice could also lead to corrupt activities, he said.

Many senior officials could still have great influence over the policymaking process even after their retirement, he added.

Zhu Lijia, a professor of clean governance research, said that the regulation on retired officials should be tightened to fight corruption.

In December, the CPC Central Commission for Discipline Inspection, China's top anti-graft watchdog, said concrete rules regarding the regulation of retired officials are urgently needed.

Unlike in the past, when retired officials were exempt from punishment, a number of former leaders have been investigated for suspected corruption in recent months.

On July 17, Yang Baohua, former vice-chairman of Hunan province's political advisory body, was expelled from the Party on allegations of accepting bribes and committing adultery. The 67-year-old retired official was probed by the top anti-graft watchdog on May 26.