City authorities said the bronze sculpture of a blindfolded woman, which was on a bayside promenade in the Philippine capital, was removed Friday to make way for a drainage and footbridge project.

However, advocacy groups for the memory of so-called "comfort women" wondered whether the Philippine government had yielded to Japanese displeasure over the memorial.

While Japan occupied the Philippines during the war, it is now one of the Philippines' top investors, trading partners and aid donors.

After the statue was installed in January, some two kilometres (1.2 miles) from the Japanese embassy, Tokyo said the move was "very unfortunate".

"The Japanese government is working hard... they also wanted to get rid of a similar statue in New Jersey," said Rechilda Extremadura, executive director of Lila Pilipina, an organisation of comfort women survivors and advocates.

"This is a desecration of Filipino women's dignity as it casts a foul insult on hundreds of Filipina sex slaves victimised under the Japanese occupation," women's group Gabriela said.

Manila's public works department could not be reached for comment and the Japanese embassy in the Philippines did not immediately respond to an email.

Historians say up to 200,000 women, mostly from Korea but also other parts of Asia including the Philippines and China, were forced to work in wartime military brothels for Japanese invasion troops.

The number of Philippine women involved is believed to number in the hundreds.

Activists have in recent years set up dozens of statues in public venues around the world, many of them in South Korea, in honour of the victims.

The statues have drawn the ire of Tokyo, which has apologised to Seoul over the issue and has since pressed for the removal of one of the statues outside its embassy there.

Philippine officials had approved the statue in Manila, which was funded by a Filipino-Chinese philanthropist to highlight the suffering of comfort women.

Asked about the statue's removal, President Rodrigo Duterte on Sunday conceded he knew little about it but urged Filipinos not to "insult" Japan.

"It is not the policy of (the) government to antagonise other nations," he said.