Indonesian peace monitors on Sunday joined an international mission tasked to ensure that a ceasefire between the Philippines and Muslim insurgents held as both sides aim to sign a peace deal this year.

The Indonesian team consisted of 10 military officials and five civilian experts on conflict prevention, and were deployed upon the request of the Moro Islamic Liberation Front (MILF) and the government.

The group is the newest foreign contingent to join the mission, which consists of about 40 others from Malaysia, Brunei, Japan, Libya and the European Union.

"Their arrival is an assurance that the ceasefire is seriously in place," the government's chief peace adviser Teresita Deles told reporters.

Deles said the 12,000-strong MILF and the government were aiming to sign a peace deal by the end of the year, following a breakthrough agreement in April in which both sides committed to create a new autonomous political region in the troubled south.

"We are expanding common grounds and we are both looking for ways on how to close distances on the most contentious issues," she said.

"There are certainly signs that the two sides are moving towards addressing each other's concerns."

"We are officially cautiously optimistic," Deles said when asked whether a final peace deal would be signed this year.

The MILF has waged a rebellion for more than three decades, originally for the establishment of an independent state in Mindanao, the southern third of the mainly Catholic Philippines.

It has however in recent years dropped its bid for full independence in favour of autonomous control over large areas in Mindanao, which it claims as Muslims' 'ancestral domain'.

The insurgency has claimed more than 150,000 lives since the Muslim rebellion began in the early 1970s.

The peace effort nearly collapsed in October 2011 after MILF rebels killed 19 soldiers who they claimed entered their area in violation of the truce.

The killings touched off fierce battles on several fronts in Mindanao, during which as many as 40 soldiers, police and civilians were killed and thousands displaced.

Both sides later agreed to forge ahead, and there had not been any fighting since January.