By Amy Sawitta Lefevre and Panarat Thepgumpanat
BANGKOK (Reuters) - A constitution that Thailand will decide on in a referendum next month is not aimed at perpetuating military rule, an official who helped write it said on Wednesday, as a former premier from a pro-establishment party rejected the draft charter.
The outcome of the Aug. 7 referendum could have far-reaching implications for Southeast Asia's second-biggest economy as a military government that took power after a 2014 coup tries to shape politics after a decade of turmoil.
Critics argue that the constitution, to replace one torn up by the military after the coup, will entrench military control at the expense of elected political parties.
The government says it will ensure stable politics.
Norachit Sinhaseni, a former diplomat and spokesman for the Constitution Drafting Committee, said the main objective of the charter was to ensure a swift return to democracy.
"We have no interest or desire to perpetuate military rule," Norachit told Reuters.
"Our number one priority is to put Thailand back on the road to democracy."
The military government would interpret a "yes" vote as a seal of approval and a mandate to govern, experts say.
A "no" vote, on the other hand, could be seen as undermining the government's legitimacy, and would raise questions about its road map to a promised general election next year.
Norachit said there were no guidelines as to what would happen if the draft was rejected.
The government says the proposed constitution will heal divisions after years of rivalry between the military-dominated establishment and election-winning populist politicians who the military says buy their way to power.
The constitution would allow for an unelected prime minister and an upper house of parliament appointed by the junta with seats reserved for military commanders to check the powers of elected lawmakers for a five-year transitional period.
It also sets out an electoral system that critics say would produce weak coalition governments.
Even some of the military's natural political allies have voiced opposition.
Former Prime Minister Abhisit Vejjajiva, leader of the pro-establishment Democrat Party, rejected the constitution on Wednesday, saying he did not see how it would help the country make progress.
"The draft can hardly be used as a tool to make the country move forward and meet the needs of the people," Abhisit told reporters.
"I cannot accept this draft."
The government has stifled dissent since the coup and is particularly sensitive about criticism of the charter, curbing debate and detaining more than a dozen activists in recent weeks for campaigning against it.
(Additional reporting by Patpicha Tanakasempipat; Editing by Robert Birsel)