
Chai said it was still not safe although leaders of the protesters promised agreed to set a way for MPs and senators to go into the Parliament's compound.
"We had bad experience when the red shirt protesters blocked the Parliament on December 15. So I decide to delay the debate to 5pm," Chai said.
Chai was referring to December 15 when the parliament voted for the prime minister and Democrat Party leader Abhisit Vejjajiva won the votes.
Red shirt protesters who surrounded the Parliament threw stones at vehicles leaving the Parliament. Some people were injured when the protesters threw items at them.
Chai said on Monday that if the MPs or senators use the way provided by the protesters, they could be harmed.
Because of the protest, the debate had already been delayed from 9.30am to 2pm and now 5pm.
Chai earlier said if the government could not secure safe passage to the Parliament, the debate will be further delayed.
Chai made the announcement by making a telephone call to journalists at a press room at 10.05am.
The red-clad demonstrators who gathered at Sanam Luang on Sunday marched to the Parliament on Monday morning to prevent Prime Minister Abhisit Vejjajiva from delivering the government's policy statement at 9.30 am.
The road to Parliament is now blocked and members of parliament are unable enter the compound.
Veera Musikapong, a leader of the United Front for Democracy against Dictatorship (UDD), the core organiser of the protest, said earlier that the red shirt group would rally continuously on December 29-30.
The UDD Red Shirt protesters are loyal to fugitive former premier Thaksin Shinawatra, who was toppled in a military coup in 2006.
Meanwhile Deputy Prime Minister Suthep Thaugsuban said the government had no immediate plans to change the venue of the policy speech. He said that if members of parliament could not enter the Parliament, it could not start in the morning as planned, and the session would be postponed to start in the afternoon, in the evening or at night.
National Police Chief Pol. Gen. Patcharawat Wongsuwan met Veera Monday morning to negotiate to request the UDD to open way for the MPs to enter Parliament by car.
They reached no agreement, but Veera said the MPs and Senators could enter Parliament only by foot, and that the UDD, which called on Prime Minister Abhisit to dissolve Parliament, would not obstruct but facilitate their walking.
Another UDD core leader, former government spokesman Nuttawut Saikua, said that the demonstration at Parliament would continue during the government's plan to deliver its policy statement.
If the venue is changed, the UDD will follow the MPs to the new venue wherever the meeting is to be held, he said. He reaffirmed that the UDD objected to the manner in which Mr. Abhisit reached the prime minister's post.