Voters in Thailand will cast their ballots on Sunday in the first general election in four years.

Attention is focused on whether the military-linked government, which took power in a coup nine years ago, can hold on to power.

Prime Minister Prayut Chan-o-cha, who led the coup, is seeking re-election with the backing of the United Thai Nation Party.

However, the latest polls show the largest opposition Pheu Thai Party, or the PTP, is leading the race with a support rate of nearly 40 percent.

The PTP is affiliated with former Prime Minister Thaksin Shinawatra, who was ousted in a prior coup in 2006. The party has fielded Thaksin's daughter, Paetongtarn, as its candidate for prime minister.

Another opposition contender, the Move Forward Party, came in second in the polls by rapidly expanding its support among young voters in the final days of campaigning.

After voters cast their ballots, the next prime minister will be selected by a joint vote of the 500-member lower house of parliament, and the military-appointed senate.

An opposition party will need to garner an overwhelming majority in the general election in order to achieve a change of government.

Voting stations will close at 5 p.m. on Sunday, followed by ballot-counting. Preliminary results are expected by the end of the day.