BEIRUT, Dec 9 (Reuters) - Hezbollah called on Friday for a Lebanese government to be formed as quickly as possible, weeks after the country elected a president and named a prime minister.

Prime minister-designate Saad al-Hariri said last month his efforts to form the government faced "stumbling blocks", testing hopes he could quickly steer the country out of political crisis.

"Everyone is responsible for looking for ways out, for solutions, and to cooperate for us to reach the necessary conclusion on the government," Hezbollah leader Sayyed Hassan Nasrallah said, referring to Lebanon's political factions. The "government ... must be formed as soon as possible."

The powerful Shi'ite Muslim movement is an ally of President Michel Aoun, elected in November to a presidency that had been vacant for 2-1/2 years because of political deadlock.

Tensions have arisen among rival leaders over portfolio distribution, the number of ministries in the new cabinet and an electoral law which needs to be passed for a parliamentary election to be held in 2017.

Lebanon urgently needs effective government to address economic and development issues such as infrastructure and refuse disposal.

Tensions have been exacerbated by war in neighbouring Syria, where Hezbollah is fighting in support of President Bashar al-Assad. Nasrallah said a victory for Assad in the city of Aleppo was imminent.

(Reporting by John Davison; Editing by Janet Lawrence) ((John.Davison@thomsonreuters.com;))