A democratically elected government will take power in Thailand at the earliest by December 2017, a senior Thai official said on Monday, after the country endorsed a military-backed constitution paving the way for a general election.

Thais handed the government of Prime Minister Prayuth Chan-ocha a convincing win in the referendum on Sunday, with preliminary results showing over 61 percent voted in favor. Full results are due on Wednesday.

A desire to see greater political stability drove the yes vote, analysts said. Thailand has been rocked by more than a decade of political turmoil that has stunted growth, two military takeovers and several rounds of often deadly street protests.

"We think there will be an election at the earliest in September or October 2017 and a new government by December 2017," Chatchai Na Chiang Mai, spokesman for the Constitution Drafting Committee, told Reuters.

Deputy Prime Minister Wissanu Krea-ngam on Monday also said an election will take place in 2017, confirming the timeline Prayuth laid out ahead of the referendum.

Before the vote, Thailand's major political parties had criticized the draft constitution, saying it would constrict democracy, including one provision calling for an appointed Senate with seats reserved for military commanders.

Few countries have had more constitutions and drafters have historically failed to produce anything lasting. Thailand has issued 19 constitutions since a constitutional monarchy replaced an absolute one in 1932.

Members of the opposition say they are biding their time until the 2017 election when, if a party they back takes power, they can try to scrap the military charter.

"We accept the result of the referendum and will wait and see what happens in the 2017 election," said Jatuporn Prompan, chairman of the United Front for Democracy Against Dictatorship.

"We will decide our next steps soon," he said.

Opposition to the military-led government was muted ahead of the vote in Thailand's northeast, once a hotbed of resistance.

A Thai student holds a poster that reads "vote no = no coup" at Thammasat University in Bangkok, Thailand, on Sunday, in protest of the constitution approved by voters. Sakchai Lalit / AP