Over 100 MPs from the UPFA have signed a no-confidence motion against Prime Minister Ranil Wickremesinghe.
Anura Priyadarshana Yapa, the general secretary of the SLFP, the party of which President Maithripala Sirisena is chair, also signed the motion, alongside opposition leader Nimal Siripala de Silva, general secretary of the UPFA, Susil Premajayantha and several other senior SLFP members.
State Minister of Finance Mahinda Samarasinghe however said many SLFP MPs, including ministers, decided to oppose the no-confidence motion.
UPFA MP Manusha Nanayakkara said the majority of MPs in Sri Lanka's parliament had signed the motion.