"My determination to work has not wavered and I will tomorrow go to work in my office as usual," he said.
Abhisit planned to return to his office at Government House today, but his security team suggested the nearby PM's official residence instead.
According to his schedule, members of the National Telecommunications Commission would see him at 7.30am today before he attends a function outside Government House.
Later, he would return to Government House to host a reception for Asean defence ministers.
Leaders of the red-shirt movement said some of their followers will also show up at the Foreign Ministry today while large numbers would remain around Government House where they could camp out for a protracted period.
Abhisit said the protests remained peaceful, while brushing aside concerns of a repeat of the bloodshed on October 7.
In that incident, police fired tear gas to disperse demonstrators, wounding about 700 and causing 10 deaths.
Abhisit believes that the red shirts would not try to disrupt the Asean Summit, scheduled for Friday at Cha-am and Hua Hin. Thir protests would be confined to Bangkok, he said.
"I believe every Thai citizen is a patriot who would not try to tarnish the country's reputation," he said.
The government would refrain from inflaming the situation so as to ensure peace, he said.
The red shirts were not expected to prolong their protests, so the government did not have a backup plan to relocate its office, he said.
The military would not disperse the crowds in order to make way for him to enter his office, he said.
While chairing the Cabinet meeting in Cha-am, he kept monitoring the situation at Government House via remote security cameras.
Deputy Prime Minister Suthep Thuagsuban, who is in charge of security, assured the Cabinet that he had the situation under control and authorities would not crack down on the crowds under any circumstances.
National Police chief General Patcharawat Wongsuwan said police could maintain order at Government House and a contingency plan was in place to ensure that the PM and Cabinet members could gain access to their offices.