The anti-government demonstration on Wednesday outside the Crown Property Bureau (CPB) in Bangkok's Dusit district has been moved to the headquarters of Siam Commercial Bank (SCB) on Ratchayothin road in Chatuchak district.
The Crown Property Bureau is a major shareholder in the SCB.
The abrupt switch to SCB Park was announced on the Facebook page of the Free Youth group about 10.15pm on Tuesday. It said the change was to avoid a possible clash with royalist groups set up to confront the pro-democracy demonstrators.
The protest at the SCB head office was set to begin at 3pm.
The SCB to announce on its Facebook page that its head office on Ratchayothin road would be closed on Wednesday. Customers were advised to use other branches nearby.
Phahon Yothin police responded by erecting steel barriers in front of the SCB Ratchayothin branch.
Bangkok police were also seen arriving there.
At the request of the Metropolitan Police Bureau, the Metropolitan Electricity Authority sent workers to install an additional eight surveillance cameras on power posts in front of the SCB head office, according to media reports.
Two were aimed at the front of the building, with the other six covering the outer area.
More security guards were also in evidence at the SCB building.
The MPB had earlier planned to deploy about 6,000 police to keep protesters away from the CPB, which was declared off-limits.
Rolls of razor wire had also been laid on the walls around the CPB. Police patrolled around the premises throughout Tuesday night.