HONG KONG (Reuters) - Media reports of a merger of Chinese state-owned chemical firms Sinochem Group and ChemChina, which is finalising a $43 billion takeover of Swiss pesticides and seed group Syngenta (>> Syngenta AG) are just rumours, Sinochem Group Chairman Ning Gaoning said.

Sources told Reuters in October that Sinochem and ChemChina were in discussions about a possible merger to create a chemicals, fertiliser and oil giant with almost $100 billion in annual revenue.

"No, no, it has been a rumour for a long while," said Sinochem Group's chairman, when asked if his company planned to acquire ChemChina, at the Asian Financial Forum in Hong Kong.

The reports of a possible merger of the two Chinese companies triggered concerns it could complicate China National Chemicals Corp's (ChemChina) acquisition of Syngenta (>> Syngenta AG), which would be the country's largest-ever foreign takeover.

(Reporting by Jessica Macy Yu and Julie Zhu; Writing by Sumeet Chatterjee; Editing by Louise Heavens)