DAVAO CITY - The Moro Islamic Liberation Front (MILF), the country's largest rebel group, said Tuesday it has sought to close ranks with a rival faction to push for a peace deal under President-elect Rodrigo Duterte.

The MILF has sent emissaries to Moro National Liberation Front (MNLF) founding chairman Nur Misuari to discuss a "common approach" after an accord it agreed with outgoing President Benigno Aquino failed to get congressional approval, MILF vice chairman Ghazali Jaafar said.

The fugitive Misuari was "very hopeful" about the prospects of ending the four-decade-long rebellion under Duterte, who will assume office on June 30, Jaafar told ABS-CBN News.

"It's unity in diversity," Jaafar said, adding there have been separate negotiations with MNLF central committee chairman Muslimin Sema since the start of the year.

Sema said the two groups could “merge” its respective peace deals with the government - the MNLF’s Tripoli Agreement of 1976 and a subsequent agreement in 1996, and the MILF’s Comprehensive Agreement on the Bangsamoro in 2014.

“We’re actually making it easy for government,” he told ABS-CBN News. “We are calling on other factions to come on board.”

Misuari has gone into hiding after being charged over the 2013 siege on the southern port city of Zamboanga.

The 2014 agreement between Aquino and the MILF would have granted wider autonomy to the country's Muslim minority, but the peace process ground to a halt after 44 police commandos died in a botched anti-terrorist raid in the remote farming town of Mamasapano last year.

Congressmen also questioned the constitutionality of certain provisions in the Bangsamoro Basic Law or BBL, which sought to establish a ministerial government in the region.