Police have arrested 28 people and a senior official in south China's Guangxi Zhuang Autonomous Region has resigned after a civil service exam was leaked in January.

The regional government had accepted the resignation of Xiao Hua, Communist Party chief of Guangxi Zhuang autonomous regional bureau of human resources and social security, because the bureau was in charge of the exam and he had to shoulder the responsibility for lax supervision, said Jiang Minghong, the bureau's director, Friday.

Police had arrested 28 people involved in the leak, Jiang told a press briefing. Xiao was not among those arrested.

The police investigation found Huang Wenliang, who was involved in setting the civil service exam, leaked the exam papers and answers to four people through instant messages for profit.

Huang had been officially arrested on charges of "deliberately disclosing state secrets," Jiang said.

Tang Changman, who was in charge of setting the exam, has been detained for "dereliction of duty".

All the applicants, except the exam cheats who had been disqualified, needed to retake the test on April 25, Jiang said.

Local applicants would received a subsidy of 200 yuan (29.3 U.S. dollars) and those out of Guangxi 500 yuan, he said.