Presidential Spokesman Rigoberto Tiglao told reporters that Guingona, who is also foreign affairs secretary, has written a letter to the Indonesian foreign minister explaining that Misuaris allegations have no basis in fact.
The Indonesian foreign minister chairs the "Committee of the 8" of the Organization of Islamic Conference (OIC) which is monitoring the governments compliance with the peace agreement.
Tiglao said Guingona had sent the letter before Misuari flew to Syria on the first leg of his Middle East tour to get the support of Arab countries.
"We believe that the OIC, through the Committee of the 8, is fully backing up the results of the plebiscite and the (new) MNLF leadership," he said.
Tiglao said retired Lt. Gen. Eduardo Ermita, presidential adviser on the peace process, has also been in touch with members of the "Committee of the 8."
"Informally, Secretary Ermita says that the OIC is recognizing the new MNLF leadership and the results of the just-concluded plebiscite and nothing in the 1996 (peace) agreement was violated," he said.
Last week, House Speaker Jose de Venecia talked to Misuari to appease the governor, who has accused the government of ignoring his appeals to postpone the Aug. 14 plebiscite for an expanded ARMM on the ground that it violated the 1996 peace agreement.
Misuari said Malacañang was behind his ouster as MNLF chairman by a 15-man council headed by Farrouk Hussein, presidential assistant for Muslim affairs.
Earlier, Tiglao said President Arroyo offered Misuari the post of ambassador to an OIC member-country. Marichu Villanueva