The Future Forward Party has confirmed its leader Thanathorn Juangroongruangkit hired lobbyist APCO Worldwide to facilitate his meetings during his visit to the United States in July.
The opposition party issued a statement on its Facebook account around midnight in response to media reports that Mr Thanathorn was suspected of hiring an American lobbyist firm.
The party said the contract sent to media organisations was not confidential. The United States government required the disclosure of such documents to ensure transparency in democracy-related activities.
The party statement said Mr Thanathorn hired APCO Worldwide LLC to facilitate his meetings with individuals and representatives of organisations and to prepare English-language documents when he visited the US from July 12 to 16. US law required a representative agent because some meetings had to be registered beforehand.
Mr Thanathorn's contract was normal practice, the party said.
The party denied allegations that Mr Thanathorn's trip was aimed at creating a situation. He went to the US only to explain his work and the situation in Thailand and to learn about the implementation of policies in another country.
The Washington DC-based APCO Worldwide is described by Wikipedia as an independent global public affairs and strategic communications consultancy firm and the second largest independently owned PR firm in the United States.
Media reported that Mr Thanathorn's contract was signed to be valid from July 1 to Dec 31, with the rate set at US$10,000 (about 306,000 baht) a month.