BANGKOK (REUTERS) - A general election in Thailand scheduled to take place this year will be delayed possibly until early 2019, the country's deputy prime minister said, after military-appointed lawmakers voted to change an election law on Thursday (Jan 25).

Prime Minister Prayuth Chan-ocha has said a general election would take place in November 2018. The date has been postponed several times since the military took power in a 2014 coup.

The National Legislative Assembly, Thailand's parliamentary body, voted to postpone enforcement of an election bill by three months to give political parties time to prepare for the vote.

The Bill is one of four needed to hold a general election, which the Constitution mandates be held within 150 days after all necessary electoral laws take effect. Delayed enforcement of one of these laws would push back the election.

"Within 150 days after the law's enforcement in September means the election will fall on January or February 2019," Deputy Prime Minister Wissanu Krea-ngam told reporters on Thursday, adding this is provided there are no further setbacks.

Mr Wissanu said the government would only be able to determine when the election can take place once the Bill is adopted in June.

Political parties said Thursday's vote was a ploy by the ruling junta to hold on to power.

The junta has not yet lifted a ban on political campaigning, although last month it issued an order that allows parties to conduct some preparation ahead of the poll.

The Puea Thai Party, whose government the army ousted in 2014, said that the amendment was a tactic by the junta to tighten its grip on power.

"It is a dishonest act by those in power to seek political advantage in power in order to hold on to power and remain in power," the party said in a statement.

Ong-art Klampaiboon, deputy leader of Puea Thai's rival Democrat Party, said a delay would hurt confidence in the government and could harm foreign investment.

Delaying the election would give the junta more time to work on how to stay in power beyond 2018, said Peter Mumford, Asia director at risk consultancy firm Eurasia Group.

"I think they are still not confident that the election will deliver the result they want," Mr Mumford told Reuters.

Thailand's Foreign Minister Don Pramudwinai said this week the international community would understand if the vote is delayed.

A US Embassy spokesman in Bangkok said the United States would like Thailand to return to democracy "as soon as possible".