The army has decided to step up its role in supporting the Centre for Maintaining Peace and Order's (CMPO) operations, citing escalating violence.
More military personnel will be deployed in areas where violence or unrest is imminent, deputy army spokesman Winthai Suvari said on Wednesday.
The army was now working together with the CMPO to ensure security for state officials and all groups of people by setting up security checkpoints and sending troops to patrol the anti-government rally sites, Col Winthai said.
The other core task the army was carrying out was sending teams to provide medical services to people living near protest areas and helping direct traffic there, he said.
In the event of confrontations, the army has teams of personnel who are trained in psychological operations and could help negotiate with protesters to defuse tensions, he said.
The Royal Thai Police, meanwhile, is planning to deploy most, if not all, of its forces at polling stations nationwide to prevent any possible attempt by anti-government protesters to disrupt the election process on Sunday.
More than 200,000 police officers plus 1,450 rapid-deployment units would be assigned to ensure security at 93,535 polling stations in 77 provinces, said Amnart Unartngarm, assistant national police chief, on Wednesday.
More than 50,000 of the force are commissioned officers, said Pol Lt Gen Amnart who described the security plan as being one of the largest police force deployments in the country's history.
Extra police and security personnel would be sent to areas considered as being at high risk of unrest, he said, referring to the polling stations in Bangkok and 10 southern provinces.
"There should not be any violence on election day because there will be many more polling stations and protesters would have to cover more stations," said Pol Lt Gen Amnart citing the latest police assessment of the security situation.
"If the number of protesters trying to obstruct the election is smaller than the number of voters, there should be no problem," he said.
He called on all sides to respect each other's rights and avoid confrontation.
Voters were being advised to avoid confronting the protesters and instead contact police officers at each polling station for help if they are blocked from getting in, he said.
The officers on duty would then try to negotiate with the protesters on the voters' behalf, he said.
Police have continued investigating the obstruction of the advance voting last Sunday and are now in the process of compiling evidence, he said.
As for progress in transporting ballot papers to polling stations across the country, Pol Lt Gen Amnart said, the police will ensure the safety of people responsible for delivering the papers. The operation has run smoothly so far.
However, a number of ballot papers destined for southern polling stations remained stuck at post offices in Chumphon, Nakhon Si Thammarat's Thung Song district, and Songkhla's Hat Yai district, he said.
Caretaker Labour Minister Chalerm Yubamrung, who oversees the CMPO, said he has assigned assistant police chief Pol Lt Gen Jakthip Chaijinda to lead about 10,000 police officers in guarding polling stations in Bangkok on Sunday.
"By saying I will not disperse the demonstrations or use weapons, I don't mean the protesters will be allowed to cause trouble and that I won't do anything to stop them. Police have to enforce the law," Mr Chalerm said.
The CMPO has also set up a team to negotiate with the People's Democratic Reform Committee (PDRC) for it to refrain from obstructing the election, he said.
The CMPO's negotiation team headed by Pol Lt Gen Jakthip comprises representatives from the armed forces, the director-general of the Public Relations Department, the media, the Election Commission, the National Human Rights Commission, and Human Rights Watch.
The team will hold talks with the PDRC tomorrow at the Pathumwan rally site at 2pm.
