The Election Commission (EC) has finalised the demarcation of constituencies, which will be published in the Royal Gazette in a few days, according to chairman Ittiporn Boonpracong.
Speaking after a seminar with newly-appointed poll inspectors, he said the redrawing of 350 constituencies has been completed, pending a final review with provincial election officials before it is officially announced.
"We don't want any mistakes because the number of constituencies decreases from 375 to 350, and [the demarcation] is not the same as it was before in many provinces," he said.
The redrawing of constituencies was expected to be completed early this month to give parties at least 30 days to conduct primary voting, before the organic bill on elections of MPs comes into effect on Dec 12.
However, a delay has sparked concern that the tentative election date set for Feb 24 could be postponed.
"It is not a cause for concern," Mr Ittiporn said.
After the organic law on the elections of MPs comes into effect, the EC will hold talks with the cabinet, the National Legislative Assembly, and the National Council for Peace and Order (NCPO) to discuss the setting of the poll date, he said.
Under the new system, some constituencies are expected to be larger than in the previous poll as there are only 350 constituency MP seats up for grabs, down from 375 seats in previous elections.
With about 66.18 million eligible voters and 350 seats, the population-to-MP ratio is 189,110 people per MP. A total of 23 provinces, including Bangkok, will see their number of MPs reduced.
According to Mr Ittiporn, the EC plans to carry on with the "visitor programme", which was introduced in 2003 to allow access to those interested in observing the general election.
He insisted that the EC has a free hand on the issue and does not need to seek prior permission from the NCPO. The issue of foreign observers is expected to be considered by the EC this week.
Mr Ittiporn said the EC will meet with foreign diplomats today to introduce the new poll commissioners to the international community.
The agency also plans to hold a briefing on the general election when the time is right, he said, adding that it is part of the EC's job to clarify the election process to the international community.
On Wednesday, Mr Ittiporn urged poll inspectors, who will be introduced for the first time in the next election, to study election laws and regulations carefully and stand by the principles of transparency and independence.
Under the organic law governing the EC, poll inspectors are responsible for examining the work of election officials, as well as looking into alleged electoral fraud and complaints.
The EC recently appointed 597 poll inspectors to help with the selection of senators between Dec 16-27 and the general election.
"The selection of senators will be our first test and the general election will be the next," he said, adding that he hopes the EC and the newly-appointed poll inspectors can work together efficiently.
