
"There is some confusion in Bangkok Constituency 10," said Ruangroj Jomsueb, public-relations chief for the Election Commission.
Some voters became bewildered because the polling booths for the two by-elections were located inside the same compound.
The MP seat in Constituency 10 has been vacant since Suwat Wansirikul - an executive of the now dissolved People Power Party - was banned from politics for five years in December.
"The ballot for the governor election is purple. The ballot for the new MP is green," Ruangroj said.
Election Commissioner Sodsri Sattayatham rushed to check the 52nd and 53rd polling stations in Constituency 10 to find out why the booths there were located so close to each other.
Space constraints were the main problem, local election officials said.
She instructed them to post a big sign in front of each booth so that voters could distinguish which booths were for which election.
Constituency 10 covers Thung Khru, Rat Burana, Bang Khun Thien and Bang Bon districts.
In other Bangkok constituencies, voters cast ballots for only the new governor.
A minor scuffle erupted at about 8am at a polling station where Prime Minister Abhisit Vejjajiva, his wife and daughter were due to show up.
Police noticed Uthen Hemwattakij, 54, loitering in front of the polling centre.
He told police he was going to directly ask Abhisit to investigate some substandard buildings in the Thonglor area and complain about corruption at the Education Ministry.
He ignored a suggestion from police and local election officials that he should file a complaint at Government House at a later date. The man also hurled abuses against police.
After he seemed to be turning unruly, he was arrested and sent to Thonglor Police Station, where he was charged with insulting on-duty officers.
Right after he was granted Bt10,000 bail, he lodged a complaint against Pol Col Kitiwat Phumthanet for allegedly twisting his hands and damaging his eyeglasses while trying to detain him.
Abhisit did not see the disturbance because he and his family arrived at the polling station at 9.50am. It was the first time for his 18-year-old daughter, Prang, to appear in front of TV cameras beside her father.
The 63rd polling place also caught some attention because ASTV was inside Triam Udom Suksa Pattanakran School where it was located.
Some voters said ASTV's content clearly favoured a certain governor candidate.
Governor candidate Atas Monsereenusorn claimed that he heard some canvassers had offered Bt500 per vote on the Thon Buri side of the city.
The Election Commission said it has already received three complaints about the governor election.
Any more protests can be lodged via the EC hotline at 1711.