China will severely punish corrupt officials regardless of the level of the position they hold, a spokesman for the country's top political advisory body said on Sunday.

When asked about Zhou Yongkang, former member of the Political Bureau  Standing Committee of the Communist Party of China (CPC) Central Committee, Lü Xinhua, spokesman for the session of the National Committee of the Chinese People's Political Consultative Conference (CPPCC), told reporters his knowledge on the issue also came from media reports.

A total of 31 high-ranking officials involved in corruption cases, including some ministry-level ones, were handled by the CPC's Central Commission for Discipline Inspection in 2013, he said.

"We are doing this to demonstrate to the whole Party and the whole society that, when we say that anyone who violates the law and Party discipline will be investigated and dealt with severely no matter who he is and how high-level his position, we mean it," he said.

This is the first time that Zhou's case has been mentioned at a high-level political press conference in China, after overseas media reports claimed that he was being probed for corruption.

The CPPCC serves as a key mechanism for multi-party cooperation and political consultation under the leadership of the CPC. The second session of the 12th National Committee of the CPPCC starts Monday until March 12.

The top political advisory body also pledged more efforts to push China's ongoing reform process.

 "The National Committee of the CPPCC fully supports the central leading team for overall reform headed by President Xi Jinping," Lü said.

The spokesman also expressed hopes that government departments could release detailed measures for deepening reform as soon as possible to make the blueprint unveiled by the Third Plenary Session of the 18th Central Committee of the CPC become a reality.

In the 90-minute conference, Lü answered dozens of questions relating to the identity of CPPCC members, China-Japan relations and air pollution.

He denied any member of the 12th National Committee of the CPPCC holds a foreign nationality, and urged members to ensure a good image.

"China does not admit dual-nationality, and does not allow foreign citizens or overseas Chinese to be selected as CPPCC members," he said.

Five members have been stripped of membership of the 12th CPPCC National Committee since February last year, Beijing Youth Daily reported recently.

Xinhua contributed to this story