Najib Razak, Malaysia’s prime minister, was on Sunday struggling to control a crisis in the Malaysian Chinese Association, the ruling coalition’s second-largest party. His difficulties raise fresh questions about his ability to fight off a resurgent opposition.

The crisis erupted after a special conference of the MCA failed to back either Ong Tee Keat, party leader and a close ally of the prime minister, or Chua Soi Lek, a former deputy leader fired by Mr Ong after revelations about his private life. Mr Najib, who leads both the Barisan Nasional [National Front] coalition and the United Malays National Organisation (Umno), the coalition’s largest party, called on MCA members to put the interests of the party and the coalition above the rivalry of the two leaders.