(Bloomberg) -- More than two million Thais who registered for early voting began casting their ballots Sunday ahead of next week’s general election, with opposition parties projected to win a majority. 

The vote is taking place amid an intensifying struggle for power in Thailand. The May 14 election pits supporters of the ruling military-backed coalition led by Prime Minister Prayuth Chan-Ocha against a pro-democracy camp of opposition parties led by Pheu Thai and Move Forward. 

While pre-election surveys show opposition parties holding a significant edge, election rules favor the incumbent. 

Sunday’s voters are among more than 52 million who will elect 500 candidates to Thailand’s House of Representatives. 

But the constitution promulgated under a military junta in 2017 gives the unelected 250-member Senate, which is filled with pro-establishment allies, a say in the selection of the next prime minister. 

That means the Pheu Thai Party, linked to former premier Thaksin Shinawatra, would need to pull together an alliance of at least 376 lawmakers to counter the Senate’s likely effort to block its candidate for prime minister. 

The party won 136 seats in 2019 under rules designed to hurt its performance, more than any other single group but not enough to prevent Prayuth, who toppled a Pheu Tha-led government in a 2014 coup, from returning to power. 

While the preliminary outcome will emerge on election night, official results will likely be announced in early July, according to the government’s preliminary time line.

The new parliament is expected to meet for the first time around mid-July and elect the prime minister later that month. Thailand is expected to have a new government in place by August. 

Thailand’s SET index rose for much of late March, when Prayuth dissolved parliament to pave way for the election and the voting date was set.

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