Hong Kong's chief executive Leung Chun-ying received millions from an Australian publicly-listed firm, according to Australia's Fairfax media.
The news has come as Leung, who is backed by Beijing, faces pro-democracy protests.
Secret documents seen by the media group are said to reveal payments of four million pounds ($6.4 million) from engineering company UGL to Leung.
Leung's office, however, clarified in a statement the payments were for his resignation from the company and not for future services.
According to Fairfax, the money was paid to him in 2012 and 2013 after he became the leader of Hong Kong. The payment was not declared on his register of personal interests.
UGL acquired a property services firm, DTZ Holdings, where Leung was Asia Pacific director.
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This agreement was made separately between UGL and Leung to ensure he did not compete with UGL and to act as "a referee and advisor from time to time", according to documents seen by Fairfax media.
Leung's office, however, said he did not provide any services after his resignation which turned effective Dec 4, 2011.
Fairfax media's two main metropolitan newspapers are The Sydney Morning Herald and The Age.