A US political advisor has sparked outrage with a trip to the Cambodian border - accusing Thailand of war crimes and 'insulting President Trump'.

Michael Alfaro visited a region in Banteay Meanchey province where Thai troops have put up barbed wire fences, allegedly occupying their neighbour's land, following rocket clashes and gunfire last month.

The Trump consultant and fundraiser visited Khmer families in the village of Prey Chan before launching a furious diatribe on a social media live stream in the rain on Friday night.

He said: 'Wait until President Trump finds out about this. Thailand, just wait, you think you're the boss? Wait 'til the president of the United States finds out exactly what happens on the border.'

The lobbyist accused Thailand of illegally seizing the strip of land, blocking villagers from travelling along a vital road.

He said: 'Since the ceasefire was reached, Thailand has continued to insult President Trump by violating the peace agreement, by putting up barbed wire fence and invading the peaceful people that live in this village.

'This is a crime against humanity and a violation of the Paris Peace Accords signed in 1991.

'President Trump wants peace, harmony and respect. What Thai people are doing is not OK, and this General, he's drunk on power and all he wants to do is pretend that he's the King of Thailand. It is not OK to kill innocent lives for his political gain.

'I would not want to be in the room when the President sees what is happening here on the border.'

Michael slammed 'Thai aggressors who choose war' as he claimed soldiers were blocking Cambodian residents from reaching their homes.

He called for stronger tariffs on the country as a punishment for allegedly breaking the ceasefire by laying fences in disputed territories.

However, bungling Cambodian officials and media appeared to mix up the advisor's connection to the US administration and labelled him a 'White House spokesman' and 'official White House correspondent'.

Furious Thai officials slammed the diehard Republican, from California, and accused him of 'being hired by the Cambodian government'.

Alfaro said he had visited the conflict-ridden region of his own volition, following similar humanitarian campaigns in Vietnam and Laos, where he rescued stricken children in floods.

Records show he was granted press credentials and interviewed the Deputy Prime Minister Sun Chanthol.

In response, Thailand initially invited Michael to their country to report on the situation.

Thai politician Chayika Wongnapachant, advisor to the Minister of Foreign Affairs, said: 'The news report by Michael Alfaro, which claimed that Thai soldiers had encroached on Cambodian territory and prevented Cambodians from moving freely to and from their homes and villages, has been addressed. Mr Alfaro has since deleted the video.

'​A high-level source has confirmed that Mr Alfaro is not an official White House correspondent, and it cannot be confirmed which news organisation he is affiliated with.

'Further investigation and inquiries have revealed that the news he reported cannot be considered factual, it is merely one individual's opinion.'

Michael said he removed his live-stream video after being alerted by the Cambodian dictator, Hun Sen, that it was stoking further tensions along the border.

'Thailand was readying tanks when they saw how angry people were about what they had been doing,' he said.

'There was someone very senior in the Thai establishment that spoke with Hun Sen and said 'let's calm down, we can work this out', which would not have happened without me visiting the region.'

A bloody military confrontation flared in long-disputed border areas as Thailand and Cambodia accused each other of instigating the violence on July 24.

Cambodia retaliated by firing rockets into neighbouring Surin and Sisaket provinces.

Officials said dozens of people have been killed and more than 300,000 displaced on both sides of the territory.

Both sides have reached a shaky truce following talks facilitated by President Trump and Malaysian Prime Minister Anwar Ibrahim, chair of the Association of Southeast Asian Nations (ASEAN).