The commission, appointed by the legislature hand-picked by the junta that took power in 2014, has faced mounting pressure to speed up the count of Sunday's vote and to address concerns about potential irregularities. The U.S., European Union, Australia and others have called for the commission to address such concerns.
Thai social media users have been less diplomatic, making hashtags such as "CheatingElection19" and "ECBusted" trend. The latest preliminary results, which the commission said were based on a count of all votes, showed that Palang Pracharath, a party allied with the ruling junta, won the most votes. The commission announced earlier that the main anti-junta party, Pheu Thai, had won the most constituency seats. Final official results aren't required until May.
Both parties have said the early results mean they have a mandate to form the next government, setting up a showdown that could last weeks and lead to instability in a country that has seen repeated political unrest over the past 15 years.
After delaying the release of a full preliminary vote count on election night and then again on Monday, the commission has done little to address concerns beyond blaming any issues in the early counting on the media failing to keep up with the raw data.
After Monday's delay, the commission said it would release a full preliminary vote count on Friday. Then on Wednesday, it said the results announced Friday would only be 95 percent of the count. Then on Thursday, without giving advance notice to the media, it went on TV to announce what it said was the full preliminary vote total, though it did not give seat totals.
As election officials began announcing various numbers, observers noted that they failed to match those in handouts the commission issued at the same time. A huge leap in the voter turnout percentage also did not appear to be supported by the absolute numbers that were issued. Other issues were more minor, such as the total vote count on one page not matching that on another.
A 208-page file showing the vote by each constituency, posted by the commission on the internet, was taken down and unavailable less than two hours after it was released. The election was for 500 seats in the lower house. Of those, 350 seats are set aside for the winner of each constituency, while another 150 so-called party list seats are divided among parties based on a proportion of the overall vote. The commission has yet to release a preliminary result for the party list seats, which is determined using a complicated formula that is meant to handicap larger parties.
While official results are due in May, the commission has said the seat allocation could change as it investigates complaints and lawsuits in some constituencies. "In the midst of public doubt toward the Election Commission, we are confident that they still have time and opportunities to prove themselves — release all information in detail, by constituency, online, so the people can scrutinize it," said Pannika Wanich, spokeswoman for the anti-junta Future Forward Party, which was in third place in the vote count.
The Asian Network for Free Elections, an established regional group of foreign poll watchers, has expressed concern over the vote, noting that the "tabulation and consolidation of ballots were deeply flawed." It noted that the announcement of some preliminary results on election night that were "wildly inaccurate" damaged the "perceived integrity of the general election."
Still, it has said it has no reason to believe the issues affected overall results. Pheu Thai, which in the latest results was in second place in the popular vote, and several other parties announced Wednesday that together they believe they won a majority of seats in the lower house and should form the next government.
Even if the coalition does secure more than 250 lower house seats, it may not get to form the government due to the country's new political system. Since the coup, the junta has used the absolute power it granted itself to rewrite the country's laws, including commissioning a new constitution and creating an electoral system that severely disadvantages parties without links to the military.
Under the new rules, an unelected 250-member Senate appointed by the junta will join the 500 elected members of the lower house in a vote for prime minister, meaning a party without Senate support would have to get the support of 376 house members to ensure its choice becomes prime minister.
The vote for prime minister will likely take place sometime in May, and Palang Pracharath's candidate, current junta leader and Prime Minister Prayuth Chan-ocha, will have a considerable advantage.