Pita Limjaroenrat, leader of Thailand's Move Forward Party, on Monday declared victory in the country's general election and said he is ready to be the country's next prime minister.
He said he would seek to build a six-party coalition including Pheu Thai, which will be worth 309 parliamentary seats, following the election.
The Pheu Thai Party said on Monday it agreed to a proposal to form an opposition coalition with the Move Forward Party and had no plan to form any other government.
Pheu Thai leaders told a press conference they were confident that a bloc with 309 seats would be enough for a stable government, but nominating a prime minister depended on legal requirements.
But uncertainty remains about whether they would be able to form the next government due to skewed parliamentary rules that allow 250 members of a military-appointed Senate to vote on the prime minister.
Despite the MFP's strong showing, analysts say it faces an uphill battle for Bangkok's Government House. That is because any winning candidate will need 376 votes across the House of Representatives and the Senate to become prime minister.
That means MFP and Pheu Thai will need the support of smaller parties to establish a new administration.
All of this means it could take weeks before Thai voters find out who will lead their new government.