A reported 10,000 supporters of a Thai opposition party which could be banned by authorities have taken to the streets in the country's biggest protest since a 2014 military coup.

Speaking to activists in the capital Bangkok, the 41-year-old billionaire leader of Future Forward, Thanathorn Juangroongruangkrit, urged people to stand up against the government and fight for democracy.

He told them "this is just the beginning" and "I think it shows that people will not tolerate dictatorship anymore".

Many demonstrators gave the three-finger salute of resistance, a symbol taken from the Hollywood film The Hunger Games.

Legal moves to dissolve the party have angered supporters who believe there is a conspiracy against it.


Image: Fast Forward supporters pictured at the demonstration

In 2014, the military staged a coup led by army general Prayuth Chan-ocha, the current prime minister, who seized power on promises to end a wave of street protests.

Earlier this year in the first general election since the coup, Future Forward came from nowhere to finish third.

Its anti-military agenda has found support among young people but has angered the country's conservative establishment, known as the junta.

On Saturday, Mr Thanathorn signed an agreement on Saturday with six parties in an opposition alliance to push for changes to the constitution drawn up by the junta before the election.

Among those parties was Pheu Thai, linked to ousted populist leader Thaksin Shinawatra, who lives in self-exile since he was overthrown in 2006. His sister Yingluck Shinawatra was ousted as prime minister by 65-year-old Mr Prayuth.

Pheu Thai won the most seats in the 500-member lower house but has adopted a quieter approach to challenging the government than Future Forward.

Image: An estimated 10,000 people were at the protest

Palang Pracharat, the pro-military party formed last year by members of the junta's cabinet, came second.

The crowd in Bangkok included veteran "red shirt" supporters of Mr Thaksin, who had previously clashed with the "yellow shirt" conservatives - hardline loyalists of the palace and army.

Since the election, Fast Forward has faced a number of legal cases, including a ruling last month by the constitutional court which saw Mr Thanathorn disqualified as a member of parliament for violating media ownership regulation.

He allegedly held shares in a media company on the date his election candidacy was registered but he has disputed the ruling.

And last Wednesday, the election commission ruled Future Forward broke the law by accepting an illegal loan from Mr Thanathorn and recommended it should be dissolved.

Image: Thailand's prime minister Prayut Chan-O-Cha led a military coup in 2014

There are not many Thais who expect the constitutional court, which is seen as being closely linked with the establishment, to disagree.

A Fast Forward spokeswoman claimed more than 10,000 people had taken part in Saturday's demonstration, but authorities have not provided a figure.

Political battles caused serious turmoil in Thailand from 2006 to 2014, including two coups and massive street protests involving different groups, police and the military.