The Tonga Public Service Association's, Mele Amanaki, claims Mr Cocker was a master of ceremonies at an event in Vava'u for the PAK - the political party headed by Prime Minister, Pohiva Tu'i'onetoa.
She said Mr Cocker breached the Public Service Act by appearing in a formal role at what she says amounted to a political rally - the launch of the PAK's platform for the November elections.
But Mr Cocker denies the claim and said he is taking legal action against the PSA and Ms Amanaki.
He said the event in Vava'u involved the launch of the government's corporate plan, was not a political event and that he is not affiliated with any political party.
Source:
RNZ Pacific