The agreement on ancestral domain was supposed to be signed on Tuesday between representatives of the government and the Moro Islamic Liberation Front (MILF) in Kuala Lumpur.
The high tribunal granted the request of local government officials in the strife-torn region of Mindanao for an injunction to block the signing, pending a decision on whether the agreement violated provisions of the constitution.
Supreme Court spokesman Midas Marquez said the justices ruled unanimously to issue the temporary restraining order.
"The solicitor general is being required to furnish official copies of the final draft of the memorandum of agreement to the court and the parties not later than August 8," he said.
Critics said the agreement allegedly gave up the sovereignty of the government over the southern region.//Deutsche Presse-Agentur (DPA) - August 4, 2008