The chairman of a Hong Kong-based State-owned conglomerate refuted on Wednesday a tip-off from a journalist that accused him of corruption and having a mistress, calling the allegations "pure fabrication and defamation."

Song Lin, the chairman of China Resources Holdings, said the allegations have damaged his image and that of his family and business. He also said that he would hold the "rumormonger" accountable by law, according to a personal statement released Wednesday on the company website.

The accusation was made by Wang Wenzhi, a journalist with the Economic Information Daily affiliated to the Xinhua News Agency on his Sina Weibo account Tuesday. Wang also alleged that Song had a long-term relationship with  a mistress named Yang Lijuan.

As of press time, the company had not made comment on the allegations.

Wang wrote in a letter addressed to China's top disciplinary authorities, the Central Commission for Discipline Inspection (CCDI), that Song helped Yang to land a job at branch offices of Swiss bank UBS in Shanghai and Hong Kong with his "work influence."

He claimed that Yang aided Song in bribe-taking and money laundering and that she allegedly owns assets worth over 1 billion yuan ($167 million) with multiple properties and money deposits under both her own name and her relatives' names.

Two photos were also posted online, in which a man who resembles Song appears to be intimate with a woman, although the pair are fully clothed. However, no information could be found to verify the identity of the two people.

The UBS legal and compliance department has launched an internal investigation into Yang, who is a Hong Kong-based investment banker, insiders were quoted as saying by the South China Morning Post on Wednesday.

Yang is reportedly a corporate client liaison officer who deals with State-owned enterprises in the Chinese mainland. The investigation order reportedly came directly from UBS in Switzerland.

This is the second time that Wang has made allegations against China Resources, after leveling accusations last year that the company was involved in corruption that "led to the loss of billions in State-owned assets." 

The company was then reportedly audited by authorities but no results have been disclosed yet. Wang said he believed there were cover-ups in the audit, which Song may have been involved in, according to Wang's blog in July 2013.

Wang also accused Song of "corruption involving a huge sum of money" in the Tuesday letter, but no further evidence was provided in the letter regarding the corruption.

"Wang's evidence is inadequate. It can at most make people question whether there is anything illegal or immoral. A public accusation requires solid and convincing evidence about ongoing incidents or those that have recently happened," said Ji Xuguang, an investigative reporter whose public accusation led to the sacking of Lei Zhengfu, a former Party chief in Chongqing's Beibei district.

Ji called for authorities to look into Song and China Resources as soon as possible, instead of waiting for the public demands for truth to build up. It is extremely difficult to know what is true and what is fabricated when allegations are put online when there are no timely official investigations, he noted.

"This practice of accusing people online is a total mess. The nation's supervision watchdogs such as the CCDI should establish or perfect their mechanisms for handling such tip-offs. For example, there should be a clear standard for information collection and verification," Ji told the Global Times.