Of more than 90 government seals printed on documents contained in her dossier, a third were found to be fake. Wang was sentenced to 14 years in prison in 2011 by a court in Hebei for crimes including offering bribes.

Similar cases have been discovered in many other places, with officials found to have lowered their ages, extended their work experience and increased the number of degrees they attained, according to media reports.

Wu Hui, a professor at the Party School of the Communist Party of China, said: "There are certain rules for selecting and promoting officials in China. For example, they must retire when they reach a certain age, and younger officials have more chances of promotion."

Yan Jirong, a professor of government administration at Peking University, said the management of dossiers has not been strict in many places in the past, and it is not difficult for officials at grassroots authorities to falsify their details.

Zhu said recent cases have exposed loopholes in dossier management.

"In many cases, falsification of dossiers was carried out with the help of a group of people and departments rather than by individuals," he said. "This exposed high-level corruption within the departments that manage officials."

It was common for officials at some grassroots authorities to collude with each other on falsifying dossiers for mutual benefit, he said.

"The key to preventing the falsification of dossiers is to ensure a public and transparent process in selecting and promoting officials," he said.

Yan said all information about major personnel arrangements should be announced and be scrutinized by the media and public.

Sun Xiaochen contributed to this story.