The Election Commission (EC) has until mid-November to redraw constituencies as enacted by the new constitution and dictated by the population growth, according to deputy secretary-general Nat Laoseesawakul.
The deadline was announced Monday when Mr Nat also explained that the constituency redesignation time frame forms a sub-deadline within a bigger deadline.
The next election must be called within 90 days of the organic law on the election of MPs being published in the Royal Gazette, most probably in the middle of this month, according to Mr Nat.
During this 90-day waiting period, the constituency redraw will take 60 days to complete, or by the middle of November. The political parties will spend the remaining 30 days organising their primary votes to select MP candidates.
Mr Nat said the size of each constituency will be determined by the size of the population in each region. For the next election, a constituency will contain about 189,000 people with registered households there, up from 186,000 people per constituency in the previous poll of Feb 2, 2014.
The new constituencies will be based on the civil registry database update made by the Interior Ministry on Dec 31 last year.
However, the EC has instructed its provincial directors to check the latest figures in the population registry in their respective provinces.
The constituencies will be typically divided along the district borderline unless a municipality has a particularly dense population. In that case, the district may be split into two constituencies.
Mr Nat said the boundary redrawing process must take into consideration the ease of travel for voters to cast their votes.
Also, the government has asked the EC to save election budget by cutting down on the number of polling stations nationwide.
In the previous election, there were about 96,000 polling stations across the country. The target is to reduce that number by 3%.
The government and the EC have agreed the next poll should take place on Feb 24 next year, and Prime Minister Prayut Chan-o-cha has insisted there is no reason for a further delay.
The deputy EC secretary-general has cautioned, however, that if the next poll is put off a further three months to May next year, which is the limit allowed by law, the constituencies may have to be re-demarcated again due to further population changes. That might also cause the election roadmap to be altered once again.
Mr Nat said the constituency redraw is not stipulated by the EC but a result of the constitution which reduces the number of constituency MPs from 375 under the previous charter to 350.
"Before the primary votes can be organised, the new constituency boundaries must be made clear first. How many registered members a party has in a constituency will be crucial for [political parties] to conduct a primary," Mr Nat said.
During the 90-day period, the National Council for Peace and Order will ease the political activities ban to let parties convene a meeting of their executives and recruit new members.