The latest demonstration on Thursday after two months of political protest comes after an overnight sit-in in Bangkok involving 50,000 people on the streets calling for Thaksin Shinawatra, the prime minister, to resign before the election on Sunday.
At the same time, Abhisit Vejjajiva, an opposition leader, said with the three main opposition parties boycotting the poll, up to 30 of parliament's 500 seats would remain empty.
This would make it unconstitutional for Thaksin's unopposed Thai Rak Thai (Thais Love Thais) party to form a government.
Due to his strong support in rural areas, Thaksin seems guaranteed to win the snap election that he called three years early in the hope of blunting the recent huge street protests calling for his resignation over allegations of corruption and abuse of power.
However, with opposition parties boycotting the election and the mass disqualification of candidates, there may not be enough MPs elected to return him to office.
According to Vejjajiva, the leader of the Democrat party, the ensuing confusion could eventually end up before the constitutional court.
"You compare this to the mob in France, it's totally different. This is such a stressful time for us. We have to do something to relieve the stress"
"All it shows is that there are still many problems ahead even after April 2, and Thaksin's legitimacy will still be questioned," said the head of Thailand's oldest party.
Some analysts are predicting as many as 60 seats left empty.
Thai law says that in uncontested seats, candidates must still win a minimum of 20% of the total eligible vote, and that all 500 parliamentary seats must be filled to make a government.
"The electoral commission will first have to deal with that. Are they going to announce there are only maybe 470, 480 MPs?
"Or are they going to keep holding elections till those seats are filled? We don't know," Abhisit said.
As for post-election strategy, the Democrats appear to be adopting a "wait and see" approach.
"We'll watch for irregularities and fraud and then look at the various movements made by the Electoral Commission, by the government or even possibly the Constitution Court."
However, in a country with a long and relatively recent history of military coups, Abhisit said he was satisfied all sides appeared to be avoiding street violence - the one development that could cause the army to intervene.
The mass street demonstrations, which began in January after Thaksin's nearly $2 billion-sale of its stake in telecoms giant Shin Corp to Singapore's government investment company Temasek Holdings, have become the place to be seen in Bangkok.
Thaksin has angered some Thais
with his business dealings
As the rallies have grown in size and stayed peaceful, they have taken on a festive spirit, offering protesters a place to get a free massage after work and to sing and dance as they try to bring down the government.
"It's another way of showing our anger," said Waranard Ashayagachat, a visa officer at the New Zealand embassy.
Arriving at the rally, he pulled an anti-Thaksin headband from his briefcase and noted that Thai protests were civilised compared to places such as France, where rioters opposed to a new labour law have been setting fire to cars and pelting police with stones.
"You compare this to the mob in France, it's totally different. This is such a stressful time for us. We have to do something to relieve the stress."