A spokesperson from the National Audit Office said an investigation group will be set up to examine the incident.

Anyone who has broken the law will be punished, the spokesperson promised.

The auditor, Zhang Hongtao, and several colleagues went to Cangzhou, Hebei Province, to audit electrical network upgrades at the Yanshan electrical power bureau.

Zhang's family said he told them the power bureau had treated them very well and had arranged several banquets for them.

Zhang called his family the day before he died, saying he couldn't pick up his child because the bureau had invited his group and some other supervision officials to yet another banquet.

That night, Zhang drank a lot of alcohol and later vomited. Zhang's family said they believed excessive drinking caused his death.

Zhang's associates and the officials from the electricity bureau left for Yangzhou City, in Jiangsu Province, just after his death.

Zhang's colleagues said most of them were too emotional over his death to stay in the office, so they went to Yangzhou to relax.

Media reports questioned the auditors' professional ethics and the audit results.

An audit office regulation issued in 2000 says auditors are not allowed to attend banquets, trips, entertainment events or parties held by companies being audited.