This is the bizarre moment an over-zealous park ranger cancels a family's day trip - after the father greeted them with the Chinese word Ni Hao.

Thai-Scottish Siranudh Scott, 28, spotted the wooden longtail boat anchored illegally while it was carrying Russian tourists off the coast of Krabi.

The conservationist raced over in a speedboat but became upset when the holidaymaker allegedly deliberately used the Mandarin greeting Ni Hao, meaning hello.

Siranudh believes it was done to insult him, as it would be impossible for the tourist not to know he was in Thailand, where Chinese is not spoken.

Clearly upset, Siranudh then accused the man of racially abusing and disrespecting him during the incident on April 15.

He said: 'I want to remind you to be a bit more respectful, because you're showing a lot of passive aggression. You are, may I remind you, a guest in this country.'

The baffled tourist appeared confused by the confrontation and acknowledged the officer's complaints.

Siranudh then added: 'Don't be racist, I heard what you said, and I heard you say Ni Hao, we're not Chinese, we're Thai, so try that again and I will have you deported.'

The Russian man, astonished by the erroneous claim that a park ranger could have him deported, says: 'I'm not being racist. Don't say that I'm racist. Really? I'm sorry.'

The conversation then continued on the sand on a small island.

Siranudh said: 'You said Ni Hao to us.'

The tourist replied: 'Ni Hao? I don't know what that means.

But the park ranger continued: 'It's just not how you say hello in Thai. Because of your attitude and disrespect towards me as a National Park ranger, your trip today is cancelled, so after this, you going to have to go back.'

The Russian and his wife protested, explaining that they did not know the correct word and used it as they assumed he would understand. They said they had 'no attitude against you' but were ordered into their boat.

'Today is finished, there's no vacation today,' Siranudh tells them.

Speaking today, Siranudh defended his treatment of the couple. He said that others agreed with him.

However, tour operators in the region who rely on holidaymakers paying for trips accused Siranudh of behaving aggressively towards visitors and risking putting them off trips.

Siranudh said: ‘To come into Thailand, and not even have the respect to know the difference between Thailand and China is extremely racist. 

‘You cannot plan a vacation here to enjoy our natural resources and ignore the Thai people who live in the country. 

‘Something as small as saying 'Ni Hao' to a Thai person, it's not only disrespectful to Thais, but to Asians as Asia is not one nationality. 

‘It would be like me going to England and thinking it was the same as Russia.'