Foreign Secretary Blas Ople gave no further explanation as to why negotiations were put off.
Unidentified diplomatic sources told AFP the MILF had yet to finalise its list of representatives who will sit on a panel and monitor the ceasefire agreed by the two sides.
Eduardo Ermita, President Gloria Arroyo's adviser on the peace process, said the MILF leadership's central committee had not yet discussed the subject.
The Filipino government has accused the MILF of harbouring terrorists, though the secessionists earlier this year denounced terror groups and agreed to partake in peace negotiations.
More than 120,000 people, mainly civilians, have died since the outbreak of hostilities between the government and separatist rebels in 1972.
Malaysia has been acting as a third-party intermediary in discussions between the two parties, which were suspended earlier this year amid a spate of bombings and attacks blamed by the military on the MILF.
The group aims to establish an Islamic state on the southern island of Mindanao.
Last month, Arroyo suspended arrest warrants issued against members of the group, including MILF Chairman Hashim Salamat, so they could partake in the summit. They were granted 90-day safe conduct passes, government officials said.
The guerrillas have been accused of providing training and protection to members of outlawed Jemaah Islamiah, an Islamist group accused of planting the bomb that killed 202 tourists in Bali last year. They are also accused of links with al-Qaeda.
The US government said it will increase development aid to Mindanao in a bid to boost living standards and secure peace in the troubled region.
The talks are largely the result of increased international pressure on the Philippines government to negotiate with the rebels.
US military advisors have been in the country for more than 12 months, training government troops to counter the guerrillas. Their efforts have proved largely ineffective.