The ballot on the left, 'suggested' by the chief of the National Council for Peace and Order (NCPO), would have only candidate numbers. Traditionally ballots have resembled the one on the right, used in 2011, with party numbers and logos, with candidate names. NCPO chief Gen Prayut Chan-o-cha reportedly proposed a ballot with only candidate names and numbers.

The Election Commission (EC) has said it will gather opinions on the format of the ballot paper for the Feb 24 general election from all stakeholders before finalising the design this week.

The move is aimed at defusing growing dissent following a report that the poll organising agency was considering omitting party names and logos from the ballot, which drew heavy flak from politicians.

EC secretary-general Jarungvith Phumma said Sunday the EC was ready to listen to opinions on the issue from all involved including the parties themselves.

In determining the ballot format, the EC must consider several factors such as fairness to all parties, protecting the rights of all voters both in the country and overseas, prevention of counterfeit ballots and the time of their publication, Pol Col Jarungvith said.

According to the election time frame released by the government on Friday, overseas voting will take place on Feb 4-16. This means the ballots must be ready and shipped abroad ahead of the voting, Pol Col Jarungvith said.

Nat Laoseesawakul, the EC deputy secretary-general, said the idea to omit party names and logos from the ballot was not floated by Prime Minister Prayut Chan-o-cha.

The omission of party names and logos was proposed at a recent EC meeting, he said.

The meeting agreed that putting party names and logos on the ballots may cause problems for voting abroad, he said.

If registered voters abroad do not receive the ballots for some reason, the EC might not be able to resend them since the ballot for each constituency will be unique, Mr Nat said.

Mr Nat denied speculation the NCPO had interfered with the EC's work, adding that the EC will finalise the official ballot format this week.

Several parties have since voiced concern that voters will be confused by the lack of the usual visual cues they have long been familiar with.

Atthasit Phankaew, leader of Thailand Political Database, a non-governmental project dedicated to increasing awareness of politics in Thailand, said the proposed omission of party names and logos on the ballot will have an adverse impact on the voting process.

"Some voters are illiterate. A lack of logos will confuse them, thus violating their right to a fair vote," Mr Atthasit said.

"The lack of party logos and names could lead to many spoiled ballots," he added.

He also warned about possible confusion resulting from the change to the way ballot numbers are assigned to constituency candidates.

Under the law on the election of MPs which will take effect tomorrow, the old system in which candidates and the parties they stand for shared the same ballot number when contesting a national election has been scrapped.

Ballot numbers will now be assigned on a first come, first served basis during candidacy applications in each constituency.

Democrat spokesman Thana Chiravinij replied Sunday that the complicated electoral rules and the confusion over the proposed ballot format would discourage voters, resulting in a low turnout.

Key Pheu Thai Party figure Chaturon Chaisang said the EC is required by law to make sure the ballot gives sufficient information about candidates and the parties they belong to.

"The proposed omission of party names and logos might be unconstitutional," Mr Chaturon said.

In previous elections, voters received two ballots -- for constituency MPs and for parties.

The former had just candidate numbers while the latter had party numbers, names and logos. The Feb 24 election will use only a single ballot for both types.