Capt Thamanat Prompow has rejected claims of a "Monaco deal", insisting his trip to the principality was a family holiday and not linked to political negotiations.
Capt Thamanat, leader of the opposition Klatham Party, said he travelled to France and Monaco with his wife and children but denied meeting former prime minister Thaksin Shinawatra or holding negotiations with other representatives of the Pheu Thai Party.
The allegations emerged after reports claimed Capt Thamanat had travelled to Monaco to negotiate parliamentary support for replacing Prime Minister Anutin Charnvirakul.
The rumours were interpreted by some commentators as a possible "red-green pact", with "red" referring to Pheu Thai and "green" representing the Klatham Party.
In a Facebook post on Wednesday, Capt Thamanat acknowledged travelling to France and Monaco but said the trip had been planned in advance as a family holiday.
"I did travel to France and Monaco for a holiday with my family. There was nothing political about it," he wrote on his Facebook page.
"I'm not the sort of person who sneaks around, and I had absolutely no need to cross continents secretly to meet Thaksin in Monaco."
He said there was also no need to prove his innocence, adding that anyone checking Thaksin's travel itinerary would find that the former prime minister was not in Monaco during the period in question.
Mr Anutin also dismissed the speculation yesterday, saying the alleged "red-green Monaco declaration" did not represent a political signal.
He joked that "when red and green are mixed together, the result is blue anyway", referring to the colour associated with his Bhumjaithai Party.
The rumours originated on July 28 after political activist Thaikorn Polsuwan posted on Facebook alleging negotiations between "red and green" political camps had taken place in Monaco.
The post claimed the talks aimed to persuade some Pheu Thai MPs, part of the ruling coalition, to abstain in parliament, weakening the government's majority and paving the way for a change of prime minister while sidelining a group referred to as the "Big Teacher", widely interpreted as Bhumjaithai.
However, the allegations remain unsubstantiated.
The post named no participants, dates or locations for the alleged meeting and provided no photographs, documents or other evidence that any negotiations took place.
