The Bangsamoro Muslims, long deprived of freedom under the U.S. and the modern Philippine state, reached the final phase in an autonomy agreement signed with the government in Manila in July 2018.
On Monday almost 3 million people are expected to vote on the Bangsamoro Organic Law (BOL) under tight security measures in Cotabato City, the regional center of Muslim Mindanao.
Local media on Sunday warned that Daesh-linked Bangsamoro Islamic Freedom Fighters (BIFF) may seek to sabotage the referendum.
Maj. Arvin Encinas, Filipino army spokesperson at the 6th Infantry Division, said that six battalions or 2,500 soldiers were deployed in the city.
Four hundred police and special operation units were also assigned to ensure poll safety, he said.
He added that in villages near Cotabato, a great many long-barreled weapons had been seized.
The Moro Islamic Liberation Front (MILF) said they were ready to help the army if needed.
The referendum is set to grant the Bangsamoro or Moro -- a collective term for Filipino Muslims living on an island in the southern Philippines -- long-awaited comprehensive autonomy.
The vote on the law is to begin on Monday in two cities, with a second round set for Feb. 6 in other areas in the region.
Once the bill is ratified, the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM) would be created.
Speaking at a rally for BOL ratification on Friday in Cotabato, Philippines President Rodrigo Duterte urged approval of the law.
Freedom for Muslims in the region was taken away by Americans in 1898 when the Spanish, who had occupied the Philippines in the 16th century, left the country to the U.S.
The Bangsamoro people also faced dire straits due to the Christian settlement policy of the Manila government, when Americans left the region to Philippine Christians after managing it until 1946.
The BOL is set to increase legal and economic gains for Muslims in the region.
With the establishment of the Bangsamoro government, courts of Islamic law will be opened in the region.
Regional authority will be handed over from the capital Manila to the Bangsamoro government.
When the BOL is ratified, the MILF group is also set to decommission 40,000 combatants of its Bangsamoro Islamic Armed Forces (BIAFF).