At least 70% of voters are expected to cast their votes in Sunday's by-elections in Songkhla and Chumphon, according to the Election Commission (EC).
The by-elections are being held in Chumphon's Constituency 1 and Songkhla's Constituency 6 to find replacements for Democrat veterans, Chumpol Julsai and Thaworn Senneam, who were stripped of their MP status.
EC chairman Ittiporn Boonpracong said the poll agency expects no less than 70% turnout in the contest, noting that the previous elections in these constituencies saw a 77.93% turnout. The EC has also stepped up security for the by-elections and taken steps to ensure that the election contest is transparent and fair, he said.
The poll watchdog has asked the Royal Thai Police and the Interior Ministry to deploy officials at polling units, Mr Ittiporn said.
Ten poll inspectors will also monitor the election process in both constituencies covering a combined 495 units, he said.
He added that local police and poll officials have also been put on standby to look into complaints and gather information about poll fraud.
Mr Ittiporn made assurances the contest would proceed under strict Covid-19 control measures.
The by-elections in the two southern provinces are said to be a two-horse race between the coalition Democrat and Palang Pracharath parties.
Democrat leader Jurin Laksanavisit said it would do more harm than good when coalition partners compete in a by-election.
He said it was an unnecessary political rivalry because it could cause friction between coalition parties while the election candidates from both parties might undercut one another in the votes.
However, he declined to say if the by-elections would lead to disunity in the coalition government.
When asked about reports that the PPRP candidate was trying to claim credit for the co-payment Khon La Khrueng scheme to stimulate spending, he said the scheme is a government policy, not any political party's.