Left-wing protesters have clashed with riot policemen as they tried to breach a barricade of barbed wire and vehicles ahead of the Philippine president's final state of the nation address.
At least six policemen and protesters were injured on Monday when authorities used water cannon to push back the protesters, who hurled rocks and bottles at them.
Police say some of the approximately 4,000 protesters started to push away the vehicles and iron railings used to block them from getting close to the House of Representatives in suburban Quezon City where President Benigno Aquino III is to deliver his speech later on Monday.
Aquino is expected to report on the progress of his fight against corruption and poverty, which have persisted in the country.
The president will make his final "State of the Nation Address" with his political clout fading and struggling to choose a successor for next year's elections that would continue with his agenda, analysts told AFP news agency.
A peace treaty with the country's largest Muslim rebel group, aimed at ending decades of fighting that has claimed 120,000 lives, is in peril as a draft law granting self-rule to the Muslim minority is stalled in parliament.
Meanwhile, economic growth slowed to a three-year low of 5.2 percent in the first quarter.
"He is entering his lameduck phase and he's losing influence by the day," said Ramon Casiple, executive director of the Institute for Political and Electoral Reform.
"He should use his remaining political capital and tell Congress to pass the BBL," Casiple said, referring to the draft Bangsamoro Basic Law that would create the autonomous Muslim region in the south and is the centrepiece of the peace plan.
The measure has languished in parliament due to outrage over the deaths of 44 police commandos in an encounter with rebels, including from the main Moro Islamic Liberation Front (MILF), in January.