Scores of construction firm owners, government officials and lawmakers - including President Ferdinand Marcos' cousin Congressman - have been accused of pocketing funds for substandard or so-called ghost infrastructure projects.

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

Criminal cases against most of the people implicated were nearly completed, Marcos told reporters.

"We don't file cases for optics. We file cases to put people in jail," he said.

"They won't have a merry Christmas... happy days are over."

Marcos put the issue of ghost infrastructure projects centre stage in his July national address, and public anger over the issue has since mounted.

Asked if his cousin Martin Romualdez will also face charges, Marcos said "not as yet", citing a lack of evidence, but adding that "no one is exempted in this investigation".

The Philippines is still reeling from the devastation caused by then Super Typhoon Fung-wong that made landfall in the country on Sunday evening, flooding hundreds of villages and killing at least 27 people.

Fung-wong came just days after Typhoon Kalmaegi hit the central part of the archipelago nation and killed at least 232 people.