The Election Commission (EC) expects the redrawing of constituencies to be completed in early November, which will give political parties at least 30 days to conduct primary voting.
EC chairman Itthiporn Boonprakong said the redesignation of constituencies for the general election has started after the EC approved a set of regulations governing the redrawing of constituencies on Tuesday.
He said provincial election directors will spend 14 days redrawing constituency boundaries, which will be put up for public input for 10 days before being forwarded to the EC for consideration.
The entire process should take about 55 days, and by Nov 6 parties should be able to proceed with primary voting before the organic bill on elections of MPs comes into effect on Dec 11.
"If we can get it done early, political parties will have more time," he said.
Meanwhile, 23 provinces, including Bangkok, will see their number of MPs reduced, according to the poll agency's announcement published yesterday in the Royal Gazette.
These provinces are assigned fewer MPs because there are only 350 constituency MP seats up for grabs in the next poll, down from 375 seats in previous elections.
The northeastern region will see the largest cut in House seats, down to 116 from 126, while the Central Plains will be allocated 76 seats, down from 82.
The southern region gets 50 seats, down from 53, while the northern region will be allocated 33 seats, down from 36.
Bangkok also sees its number of House seats reduced to 30, from 33, while seat numbers in the eastern and western regions remain unchanged at 26 and 19 respectively.
The allocation of seats is based on a civil registry database update made by the Interior Ministry on Dec 31 last year.
With about 66.18 million eligible voters and 350 seats, the population-to-MP ratio is 189,110 people per MP.
Political parties have voiced frustration over the EC's guidelines on "dos and don'ts" after the National Council for Peace and Order (NCPO) eased its ban on political activities last Friday and ordered the EC to redraw the new boundaries before the organic law on the election of MPs takes effect.
Democrat Party director, Sutham Rahong, said the EC's guidelines are not useful because they do not address party concerns about political campaigning.
In its order, the NCPO prohibits parties from using social media to solicit votes, which triggered a debate over what is and is not considered vote garnering.
He said the issue is expected to be raised at a meeting between the EC and party representatives planned for Sept 28, but it's unlikely the EC's explanations will be conclusive.
The EC's guidelines have been sent to parties along with a letter inviting them to attend the Sept 28 meeting, in which the EC will give a lecture and answer questions about the new election laws and how the parties fit in.
"Even if there is a Q&A session, it's no guarantee that the EC's answers are definite. If it has to take the issues to the NCPO like it did previously, the discussion is not as useful as it should be," he said.