Troops will be deployed in the Thai capital next week for the planned "shutdown" of Bangkok by demonstrators trying to overthrow the government.
The government is mobilising 14,880 police and soldiers for the mass rally, officials said on Wednsday.
"Our goal is to prevent any violence or clashes," national police spokesman Piya Uthayo said in a televised briefing.
Officials say the government is ready to declare a state of emergency if needed to deal with any unrest, following several outbreaks of street violence in which eight people, including a policeman, have been killed and hundreds wounded.
Prime Minister Yingluck Shinawatra has called February elections following weeks of opposition street protests.
Yingluck's government still enjoys strong support and is expected to win the election if it goes ahead, but demonstrators have vowed to block the vote,and say they will occupy the capital from January 13 until they topple the government.
Worst strife since 2010
Critics say the protesters want to provoke fresh clashes in the hope of triggering a military coup on the pretext of restoring order- an accusation the demonstrators deny.
The demonstrators- primarily southerners,urban elite,middle-class and royalists- want an unelected "people's council" to run the country.
Thailand has been periodically shaken by political bloodshed since Yingluck's older brother Thaksin Shinawatra was toppled by royalist generals in a coup seven years ago.
The recent civil strife is the worst since 2010, when more than 90 people were killed in a bloody military crackdown on pro-Thaksin Red Shirt protests under the previous government.
Ex-deputy premier Suthep Thaugsuban was due in court Wednesday to face a murder indictment over those deaths, but he asked for another postponement because he is leading the current protests.