UPDATE 1-Ex-minister Diab on course to be named Lebanese PM -sources

Former education minister Hassan Diab looks set to be named Lebanon's new prime minister on Thursday, senior political sources said, a move that would thrust a little-known engineer to the forefront of efforts to tackle an acute economic crisis.

President Michel Aoun is due to hold formal consultations with Lebanon's 128 lawmakers on their choice for prime minister throughout the day, and must designate the candidate with the greatest support. Diab emerged as a candidate for the position at the last minute when outgoing Prime Minister Saad al-Hariri withdrew his candidacy for a job that must be filled by a Sunni Muslim in Lebanon's sectarian system.

As things stood on Thursday morning, Shi'ite groups Hezbollah and Amal, in addition to Hezbollah's biggest Christian ally, the Free Patriotic Movement (FPM), will all nominate Diab, three senior sources familiar with each group's position said. With the Iran-backed Hezbollah and its political allies holding more than 70 of the seats in parliament, Diab should emerge with the largest amount of support.

Hariri, who is aligned with Western and Gulf Arab states, resigned on Oct. 29, prompted by protests against a ruling elite accused of overseeing rampant state corruption. (Writing by Tom Perry; editing by John Stonestreet)