Thailand's military government, which took power in May last year, appointed a committee to draft the country's 20th constitution after a previous draft was rejected, delaying promised elections until at least 2017.

The junta-appointed legislature dismissed the military-backed constitution in September after it was met with strong opposition by almost all sides of the political divide, in effect playing into the military's hands by prolonging army rule.

A major point of contention was the creation of a National Committee on Reform and Reconciliation Strategy that would be dominated by the military, allowing it to exercise power over the executive and legislative branches in a vaguely defined "crisis" situation.

The new, 21-member committee has six months to write a new draft and will need approval by the legislature and to put the constitution to a referendum, something that would delay elections until at least 2017, said deputy Prime Minister Wissanu Krea-ngam.

Prime Minister Prayuth Chan-ocha also appointed 200 members of a National Reform Steering Assembly to oversee the junta's political and economic reform plans, with nearly half from the police and military.

The assembly replaces the now-defunct National Reform Council which was dissolved after lawmakers voted to reject the constitution draft in September.

The military took power in May 2014 after months of political unrest. The junta, formally known as the National Council for Peace and Order, scrapped the constitution and set about writing one that critics say was aimed at consolidating the army's already-sweeping powers.

Kan Yuenyong, an analyst at Siam Intelligence Unit think tank, said the junta's aim of a constitution that gives the military overarching powers remained unchanged.

"At the end of the day, the junta has the same aims it did before, namely, it believes the political system doesn't work and they need an umbrella organization to oversee the country and to weaken the electoral process but how they will do that and make it more palatable to people remains to be seen," he said.

Deputy Prime Minister Wissanu Krea-ngam said Meechai Ruchupan, an adviser to the junta, would head the new committee.

Meechai led a junta-appointed panel that drafted the 2006 constitution, dubbed the "anti-Thaksin" charter because it appeared aimed at preventing the return of ousted former Prime Minister Thaksin Shinawatra.

Thaksin was deposed in 2006 after being accused of corruption. His sister, Yingluck, was removed from power in May 2014 after being found guilty of abuse of power. Days later, the army staged a coup, ending months of protests in Bangkok aimed at ousting Yingluck's government.