(Reuters) - Philippine President Benigno Aquino will ask Southeast Asian leaders to issue a collective statement denouncing China's reclamation in disputed waters, an official said on Monday, as the army expressed concern over expanding building works.

Recent satellite images suggest China has made rapid progress in building an airstrip suitable for military use in contested territory in the Spratly islands in the South China Sea and may be planning another, moves that have been greeted with concern by G7 states and Asia.

"The president will raise...definitely the reclamation issue," Foreign Ministry official Luis Cruz official told reporters. "We would aim for a collective statement, this time on the issue of the reclamation of some features in the South China Sea."

Malaysian Prime Minister Najib Razak hosts the 26th Association of Southeast Asian Nations (ASEAN) summit which begins on Friday.

China claims most of the potentially energy-rich South China Sea, disputed in parts with the Philippines, Vietnam, Malaysia, Brunei and Taiwan, and denies accusations its actions in its own territory are provocative.

Philippine military chief General Gregorio Catapang showed journalists aerial surveillance pictures of China's reclamation work.

"This is worrisome," Catapang said. "This is our main concern now. This is the issue that we are now trying to address."