Thousands of Filipinos marched in Manila on Sunday to vent their anger over a ballooning scandal involving bogus flood-control projects believed to have cost taxpayers billions of US dollars.

Rage over the so-called ghost infrastructure projects has been mounting since Philippine President Ferdinand Marcos put them centre stage in a July state of the nation address that followed weeks of deadly flooding.

Marcos had said early last week he did not blame people for protesting "one bit" while calling for demonstrations to remain peaceful. On Sunday they largely were.

But several groups of young men threw rocks and bottles at police and set fire to the tyres of a trailer used as a barricade near a bridge leading to the presidential palace.

Police arrested 17 mostly young people, local authorities said.

The Department of Finance has estimated the Philippine economy lost up to 118.5 billion pesos (US$2 billion) from 2023 to 2025 due to corruption in flood control projects.

Earlier this month, the owners of a construction firm accused nearly 30 House members and Department of Public Works and Highways officials of taking cash payments.

The scandal has already sparked leadership changes in both houses of Congress, with House speaker Martin Romualdez, a cousin of Marcos, tendering his resignation earlier this week as an investigation got underway. (AFP)