A former Sri Lanka health minister has signed an agreement with opposition parties, trade unions and professionals to scrap the country's powerful presidential system and carry out other democratic reforms if he beats incumbent Mahinda Rajapaksa and wins January's presidential election.

Maithripala Sirisena led a revolt in Rajapaksa's Sri Lanka Freedom Party last month and announced he will run in the Jan. 8 election, with the backing of the country's main opposition United National Party.

Sirisena pledged Monday to make the police, judiciary and government bureaucracy independent from political interference within 100 days of being elected.

He has accused Rajapaksa of nepotism, corruption and turning the country into an autocracy. Eight other ministers and lawmakers have also defected from the government to support Sirisena.