Thailand's surging opposition party held a victory rally this afternoon to celebrate its win in the country's elections despite the military vowing to retain control.

The progressive liberal Move Forward party won 112 seats in the national poll - far more than the army incumbent's 23 seats - and formed a coalition with former Man City owner Thaksin Shinawatra's Pheu Thai party, which also won 112 seats.

Footage shows youthful leader Pita Limjaroenrat, 42, as he was mobbed by supporters at the Democracy Monument in the capital Bangkok on Monday afternoon.

However, the winning party now faces an uphill struggle against an electoral system rigged by the military to ensure army chiefs retain control through a system of 250 military-appointed old-age senators who cast the deciding votes.

The senators - branded 'establishment dinosaurs' by critics - have vowed to reject the Move Forward party due to its reformist pledge to make legalize criticism of the country's monarchy and abolish national service.