Thailand's top court has rejected the ruling party's attempt to amend the constitution, dealing a political defeat to the government.

But, the Constitutional Court's Wednesday ruling turned down a request from the government's opponents to dissolve the ruling party.

The ruling follows another political setback to Prime Minister Yingluck Shinawatra's government when the Senate last week rejected its bid to pass a political amnesty bill that critics said was designed to bring home deposed former leader Thaksin Shinawatra, who is Yingluck's brother.

Analysts say Wednesday's ruling could deepen Thailand's political crisis by angering Thaksin supporters and emboldening his opponents, both of whom have gathered for mass protests recently.