International humanitarian agencies have raised concerns over their safety when delivering aid to thousands of people displaced in the southern Philippines, officials said Thursday.

Defense Secretary Gilberto Teodoro said the issue was aired during a meeting between a special government taskforce on refugee and various UN agencies.

"One of the issues raised was the security of international aid workers and other NGOs (nongovernmental organizations) who are helping," in the relief operations, he said.

"We are concerned with their safety and would provide as much security assistance as possible," Teodoro told reporters after the meeting.

But providing troops to escort food convoys could also strain soldiers on the frontlines against the Moro Islamic Liberation Front (MILF), which has been locked in heavy fighting with troops since August.

"I'm realistic enough to note that it may stretch our resources," Teodoro said, as he warned against a continuing rise in hostilities after the Islamic holy month of Ramadan ended Wednesday.

Government has suspended talks with the MILF after they attacked several towns across the southern island of Mindanao in August, killing dozens of civilians and burning more than 100 homes.

More than half a million have been affected by the fighting, either indirectly or directly, government said.

Of that total, more than 100,000 are inside evacuation centers.