The Election Commission (EC) is struggling to overcome legal hurdles that could render Sunday's vote invalid as opponents of the poll are expected to mount legal challenges to have it nullified.
The EC will consult a full panel of its legal counsellors on Saturday to discuss the issue relating to the 28 constituencies in the southern provinces that still have no candidates because protesters blocked candidate registration in late December, among other issues.
The move comes amid concerns that after the poll, opponents of the election will file lawsuits to have it invalidated on the grounds that it must be held nationwide on a single day, as stipulated by the constitution.
EC chairman Supachai Somcharoen said on Friday the commission and its legal advisers will study what is on the books to deal with the issue.
Mr Supachai said they will discuss candidate re-registrations in the 28 southern constituencies which have no candidates.
They will consider whether candidate re-registrations should be authorised by another royal decree issued by the caretaker government or should be authorised by an announcement by the EC, Mr Supachai said, adding that the issue is unprecedented.
He also said the EC and its legal advisers will consider whether the elections for the 28 constituencies, if organised later, would mean the vote did not take place nationwide on a single day.
He said there are concerns that holding elections in the 28 constituencies on other dates after tomorrow's general election could risk violating the royal decree issued on Dec 9, which requires the general election must take place on the same day.
"There are several factors that could invalidate the poll. But the EC has no authority to decide. It is the Constitution Court that has the authority to rule on the matter if petitions are lodged," Mr Supachai said, adding the problem has never happened before. He said the EC will try to explore legal channels to find solutions to the problems.
He said the vote count can begin and proceed at polling stations that are not disrupted tomorrow.
However, the EC will not announce poll results until after a new round of advance voting in the 83 constituencies, which could not hold advance voting last Sunday due to disruptions by protesters. The new round of advance voting is to be held on Feb 23. Ballots from overseas voting are also to be delivered to the country.
All the poll results will be officially announced after all the votes from the advance voting and from overseas voting are combined, Mr Supachai said.
He said he had received information that anti-election protesters in the 66 provinces, which managed to hold advance voting last Sunday, plan to launch campaigns against tomorrow's poll as well as to surround some polling stations.
Mr Pravich said the EC has also issued regulations for voters who cannot go to vote because of protests.
They can write to the EC within seven days after the election, saying they could not vote because they were unable to travel to poll booths as the roads were blocked by protesters.
Prominent legal expert Meechai Ruchupan said the reason the charter requires a general election to be held in a single day is to ensure fairness.
If the poll is held in excess of one day, it may give unfair advantages to certain political parties, Mr Meechai said on his website.
He said voters in a constituency marked for later election would know how other people have already voted in other parts of the country.
"It's human nature that when one knows who is winning or losing, that might weigh on their choice of who to vote for," he said.
He added some may be induced to choose candidates who are behind in the vote count, so it could be argued they vote purely on the basis of sympathy.
In a close race, not holding an election in a single day can lead to electoral fraud, he said.
!Mr Meechai said the EC should have taken a firm stand. If it thought the process of organising tomorrow's election was unconstitutional, it should have refused to let the poll be held.
Caretaker Prime Minister Yingluck stressed the importance of the poll, saying attempts to disrupt it will reflect negatively on the country, which will be viewed as undemocratic by foreign countries.