A man casts his vote in a booth where voters have to turn their backs to the rest of the polling station, raising fears that people can see how ballots are marked.

The PAD said the Election Commission (EC)'s decision to change the position of polling booths nationwide was illegal as it allowed people outside the booths to get a glimpse of who the voters were voting for.

Meanwhile, a group of legal experts will today file a complaint with the United Nations, asserting that the new set-up of the booths was a human-rights violation.

The Democrat Party and the People's Network for Elections in Thailand (P-Net) also criticised the EC for the change, saying it violated the Constitution.

The PAD's action follows criticism from many voters, including former prime minister Anand Panyarachun, who were unhappy with the way the EC had arranged the ballot booths, forcing them to cast their ballots by turning their backs towards the polling stations staff and observers.

It is thought that most voters will have marked an "X" in either box No 2 for the Thai Rak Thai Party candidate or in the box for a "no vote" to show their rejection of a return of Thaksin Shinawatra to the premiership. On the ballot sheet, the No 2 box was in the upper left-hand corner while that of the "no vote" was at bottom right.

Suriyasai said he believed some people outside the booths could easily have seen where a person was making their mark on the sheet.

The PAD's representatives will ask the court to rule this election illegal and to bar the EC from announcing the results, he said.

In previous elections, the booths were arranged in such a position that no one else could see a voter's choice.

Legal expert Bhodhiphong Bun-luawong said he and some of his

colleagues would ask the UN to declare the election invalid as the EC had violated the human rights of the voters.

P-Net coordinator Somchai Srisutthiyakorn said the group would ask the National Human Rights Commission to rule on whether the EC had violated people's rights.

The commission would then pass the complaint on to the Constitution Court to rule whether the EC broke the charter.

"If the EC is found guilty, all four of its current members will have to resign," he said.

Democrat Party spokesman Ong-art Klampaiboon said the change in the position of the booths could violate Section 104 of the Constitution as it left the act of voting open to other people to see where voters made their marks.

EC secretary-general Ekkachai Warunprapha, meanwhile, said the change came after the EC received complaints that the old set-up allowed people to carry out illegal activities inside the booths.

"Some people took pictures of their ballots to show to people who were bribing them so they would get paid," he said.

After receiving a number of complaints yesterday, however, Ekkachai said the EC would consider switching to the old set-up.

The EC stated in a letter to local election offices on March 9 that a change in the position of the booths would make it more convenient for voters in elections from the local to the national level.

Former PM Anand, who voted in Watthana district, said the new setting of the booths could allow ill-intentioned people to peek into the booths and know which candidates and party the voters voted for.

"I hope the EC will look into the matter," he said.

When Chamlong Srimuang, one of the PAD leaders, cast his ballot in the morning, television cameras clearly showed that Chamlong had cast a "no vote".

Wittaya Karndi, a voter in Bangkok's Bueng Kum district, reportedly refused to vote despite going to the polling station.

He said he had asked staff to change the position of the booths back to the old set-up, which would prevent other people from seeing who he voted for.

But none of them responded to his request, so he "sanctioned" himself, he said.