The disruption of acting Prime Minister Niwatthamrong Boonsongphaisan's efforts to organize an election came hours after gunmen attacked anti-government protesters, killing three.
The turmoil comes as the government loyal to ousted former premier Thaksin Shinawatra squares off with opponents backed by the royalist establishment over who should be prime minister, in the latest phase of nearly a decade of rivalry.
Hundreds of protesters converged outside an air force school in north Bangkok after word spread that Niwatthamrong was meeting commission officials there. They had put off talks at another venue the previous day because of security fears.
"We are here to tell Niwatthamrong that there is no point standing in our way," Chumpol Jumsai, a leader of the anti-government protesters, told the crowd from on top of a truck shortly before hundreds of protesters evaded police and streamed through a side entrance of the compound.
Commission member Somchai Srisutthiyakorn said the meeting was being abandoned and Niwatthamrong was leaving. "We will have to meet another day," he said.
The government sees a general election as the best way out of a crisis that threatens to tip Southeast Asia's second-biggest economy into recession and has even raised fears of civil war.
Its enemies know the government would be highly likely to win a poll, and want electoral reform aimed at ending the influence of former telecommunications tycoon Thaksin before another vote is held.
Somchai later told Reuters a tentative date of July 20 for the election looked improbable,. "We may have to push back the polls," he said.