Prime Minister Prayut Chan-o-cha is highly likely to remain prime minister after Sunday's election.

Of the 93% of unofficial poll results announced by the Election Commission (EC), Pheu Thai won the most seats in the constituency system with 125 while the Palang Pracharath Party (PPRP) came in second on 97, followed by the Bhumjaithai Party (39), the Democrat Party (29) and the Future Forward Party (26) as of 4am Monday.

However, according to the unofficial results, the PPRP led with 7.1 million votes, followed by Pheu Thai (6.9 million), Future Forward (4.4 million), Bhumjaithai (2.6 million) and the Democrat Party (2.1 million).

As a result, the PPRP is likely to win a higher number of party-list seats than Pheu Thai.

As such, the two parties would be more or less level with each other in terms of both constituency and party-list MPs.

A Pheu Thai source said party leaders were surprised at the number of votes won by the PPRP. As a result, Pheu Thai had not yet contacted other parties to form a government as it wanted to wait for the full unofficial outcome first.

If parties which belong to the pro-democracy camp such as Pheu Thai, the Future Forward Party, and the Puea Chat Party, cannot muster at least 251 House seats, or more than half of the total of 500 seats, it will be difficult for Pheu Thai to form a government and the PPRP must be allowed to form a government instead because it has more bargaining power than other parties, the source said.

Political observers noted that the Democrat Party disappointed hugely after it won only 29 constituency seats as of 4am and lost all its seats in Bangkok to the PPRP and FFP.

As a result, Democrat leader Abhisit announced his resignation at 9.50pm, honouring his promise to quit if the party won fewer than 100 seats.