ISTANBUL (AFP) - Syria's opposition National Coalition on Saturday named a moderate Islamist as its interim prime minister, in a key step towards forming a government.

Ahmad Toameh, elected during an opposition meeting in Istanbul, replaces Ghassan Hitto who resigned in July after just four months in the post without managing to form an opposition cabinet from among the fractious group.

Toameh, a 48-year-old dentist by training, now faces the arduous task of cobbling together a government to govern the regions in Syria under rebel control.

He vowed to form a cabinet that will work on the ground alongside rebels fighting the regime of President Bashar al-Assad, including to organise the distribution of humanitarian aid in the war-torn country where more than 110,000 people have been killed and millions displaced since the start of the crisis in March 2011.

He vowed that "a new republic will be established in Syria... It will be a humane republic, where there will be no room for killers and criminals... no room for any denial of civil rights".

He received 75 votes, with 10 voting against him and 12 representatives filing blank ballots.

The National Coalition has been led since early July by Ahmad al-Jarba, a tribal chief and veteran dissident who fled abroad in August 2012 after being released from a second stint in the regime's jails.