Thailand's election authority on Wednesday launched a bid to knock-out the country's main anti-army opposition over alleged illegal loans by the party's leader, a billionaire who has harangued the military-backed government since seizing the political limelight.

The Future Forward Party (FFP) rode a youth-propelled wave to become Thailand's third largest grouping in March elections, scooping up over six million votes - an unprecedented number for an upstart party.

Its emergence -- and sharp takedowns of the military-aligned establishment -- has rattled the army and its allies in a kingdom that has seen at least a dozen coups since 1932.

Thailand's courts have played a central role in taking out political threats to the establishment and no civilian government has completed its term since 2006.

Since surging into parliament, senior FFP members have been battered by legal woes.

Last month the Constitutional Court stripped Future Forward's leader Thanathorn Juangroongruangkit of his MP status over a media shareholding case, a decision that could lead to jail.

The same court will now decide whether to press ahead with hearings to dissolve the party, after a complaint was made by the Election Commission.

Last month the Constitutional Court stripped Future Forward's leader Thanathorn Juangroongruangkit of his MP status
Last month the Constitutional Court stripped Future Forward's leader Thanathorn Juangroongruangkit of his MP status AFP / Lillian SUWANRUMPHA

The commission accused Thanathorn of illegally loaning 191.2 million baht ($6.3 million) to his party in "violation of the political party law".

If the highly-interventionist court takes the case and eventually disbands Future Forward, its 78 MPs can remain in parliament if they switch allegiance to other parties.

The military-backed administration of former junta leader Prayut Chan-O-Cha will likely be lying in wait for any defections, desperate to boost its razor-thin majority in the lower house.

In March, the Constitutional Court disbanded another anti-military party shortly before the election, ruling that its nomination of a Thai princess as prime minister was "hostile" to the constitutional monarchy.

Thanathorn says the cases against him and FFP are politically motivated to silence a party with radical ideas such as ending conscription and addressing the wealth gap in one of the world's most unequal countries.

Future Forward has also come under fire for an unprecedented political objection to a royal command in a country where the monarchy -- one of the richest in the world -- is at the apex of power.

The palace is buttressed by the military and business elite and protected by one of the world's harshest anti-defamation laws.