BANGKOK (REUTERS) - Thai Deputy Prime Minister Prawit Wongsuwan said on Wednesday (Jan 4) a general election will be held this year after doubts were raised by a member of the national legislative assembly.

Thailand's next polls will restore civilian rule following a 2014 coup, and will be the first under a new constitution, approved in a referendum last year, that critics say will ensure military oversight of elected governments.

"We can't move it. It has its time frame. What the National Legislative Assembly has said is their problem," General Prawit, who is also defence minister, told reporters in Bangkok.

A member of the military-appointed National Legislative Assembly said on Monday (Jan 2) the election would have to be delayed until 2018 to allow time to pass laws needed to hold it.

Prime Minister Prayut Chan-o-cha, a former army chief who led the 2014 overthrow of the last elected government, has sought to dispel concern his military government might delay the restoration of democracy, dismissing talk among politicians that the vote would be delayed.

"In terms of the roadmap, you mustn't heed what anyone else says," Mr Prayut told reporters in Bangkok.

The army said the 2014 coup, the second takeover in six years, was necessary to restore stability after months of sometimes deadly street protests against the government of Prime Minister Yingluck Shinawatra.

Some Western governments have pressed for a swift return to democracy.

The junta has struggled to kick-start a lacklustre economy which, after years of impressive growth, is struggling amid high household debt and low consumer confidence.

The next step in the transition back to civilian rule is for new King Maha Vajiralongkorn to endorse the new constitution.

The King, who came to the throne following the death of his father, King Bhumibol Adulyadej in October, has until next month to do so.

Critics say certain elements of the constitution could stifle democracy including a provision establishing an appointed upper house Senate with seats reserved for military commanders.

Some politicians have suggested that the election should be postponed until 2018 because this year, the country will be focusing on preparations for the cremation of the late King and the subsequent coronation of the new one.

Mr Amnuay Klangpa, a former lawmaker from Ms Yingluck's party, urged Mr Prayut to stick to his word on the election timing.

"I hope the prime minister keeps his word and holds elections according to the government's roadmap at the end of this year," he said.