Turmoil in tiaras at Miss Universe pageant in Thailand

But the runup has been dominated by the off-stage antics of the coiffed contestants and their Thai hosts, escalating into a feminist firestorm drawing the attention of Mexico's president.

On Tuesday, Mexican delegate Fatima Bosch staged a dramatic walkout -- in an evening gown and high heels -- from a meeting where she was lambasted by Miss Universe host Nawat Itsaragrisil.

In a livestream of the event, Nawat seemed to single out Miss Mexico and call her a "dumbhead" during a dispute over her apparent failure to post promotional content on her social media.

He has since denied using the term.

But after Nawat called for security to intervene, the besashed Bosch staged a walkout flanked by Miss Iraq, who wore a bejewelled floor-length robe.

"What your director did is not respectful: he called me dumb," Bosch told a press gaggle. "The world needs to see this because we are empowered women and this is a platform for our voice."

Other beauty queens appeared to rise in solidarity with Bosch, before freezing as Nawat warned those still wanting to participate should "sit down".

The drama provoked a reaction from Mexican President Claudia Sheinbaum, who on Wednesday said Bosch was an "example of how we women should speak out" in the face of aggression.

"In public events, I say women look prettier when we speak out," she said. "So my recognition goes to this young woman."

Mexico's embassy in Thailand said on its Facebook page it is in "constant communication" with Bosch and her relatives, but did not respond to AFP's request for further comment.

- 'Betrayed' -

Nawat, meanwhile, has seen his own behaviour publicly shamed by the Miss Universe Organization.

"I will not allow the values of respect and dignity toward women to be violated," president Raul Rocha said in a grandiose podium speech.

"Unfortunately, Nawat has forgotten the true meaning of what it means to be a genuine host," he added, accusing him of "public aggression" and saying his role in the pageant would be limited.

Afterwards Nawat appeared at a press conference wearing a tuxedo and openly weeping as he theatrically dabbed his eyes with a handkerchief, claiming he had been "betrayed".

But he had a starring role in the opening ceremony of the competition on Wednesday night, standing contrite before the assembled grinning beauty queens where he offered an apology.

"I am a human," he said. "The pressure is a lot."

"I have not intended to harm anyone because I respect all of you. I have to say I am so sorry."

It is not the first time the mogul -- also the president of Thailand-based pageant Miss Grand International (MGI) -- has been caught in a spat fit for a telenovela.

Last year, contestants of MGI were incensed after having to sit on plastic chairs and eat peanuts on a tourist boat in Cambodia instead of a highly-anticipated luxury river cruise.

Even before the fight with Miss Mexico, this year's Miss Universe pageant had been struck by controversy.

Thai media reported police investigated participants for allegedly filming clips featuring pillows branded with the name of an online casino at their hotel, a breach of the country's strict gambling laws.

Barring any further drama, the pageant final is set to be held on November 21 in Nonthaburi province.

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