Syria's new opposition coalition edged closer on Friday toward choosing a prime minister to lead a transitional government after three days of talks in Cairo that furthered the dominance of the Muslim Brotherhood.

Former Prime Minister Riad Hijab, a longtime apparatchik in President Bashar al-Assad's Baath Party before he defected in August, is the strongest candidate for the job, delegates said.

Hijab, who is backed by Jordan and Gulf states, is likely to be chosen before or during a gathering in mid-December of the Friends of Syria, according to coalition insiders.

The grouping of dozens of nations had pledged mostly non-military backing for the revolt but is worried by the influence of Islamists in the opposition.

A popular uprising erupted in March 2011 against Assad's autocratic rule in which 40,000 people have been killed and hundreds of thousands forced to flee the country.

Coalition member Louay Safi said the prime minister would be the point man for the coalition with the international community and act as the head of an alternate Cabinet ready to fill the political and security void if Assad falls from power.

Members of the new government cannot be members of the coalition, which numbers 60.

"I think Hijab has the best chance. He has taken big risks to defect and has since come across as a balanced and composed choice," said coalition member Munther Bakhos, a veteran opposition figure forced to flee Syria during the 1970s, as bloody repression by Assad's father, late President Hafez al-Assad, intensified, eventually killing many thousands.

Under internal coalition rules reached late into the night, the prime minister will be elected by a simple majority in the coalition, in which the Brotherhood and its allies have more than 50 per cent of the seats.

Candidates must have contributed to the 20-month revolt against Assad and not be tainted by corruption, according to internal rules reached at 2am (midnight GMT).

NEW EXECUTIVE BODY

The coalition earlier on Friday created an executive body, less than a month after the group came into being with Western and Arab support.

The 11-member "political assembly" will be headed by moderate preacher Moaz al-Khatib, the current president of the coalition.

They will include his two vice presidents and the coalition's secretary general, Qatari-backed businessman Mustafa Sabbagh, who has emerged as one of the most powerful figures in the new structure.

But the delegates failed to agree on the names of the 11 members after a lengthy election procedure and postponed deciding on the issue, delegates said.

Hardball politics have overshadowed the three-day proceedings in Cairo, with the Brotherhood becoming an overwhelmingly powerful kingmaker.

Since the coalition was set up in Qatar earlier this month, the Brotherhood has swiftly assembled a de facto majority bloc, according to insiders keeping track of changes in the membership of the coalition.

The revolt against four decades of rule by Assad and his late father revived the Brotherhood's fortunes after decades of repression that killed many thousands of its members, and opened more sources of financing for the organisation from exiled conservative Syrians.

France, Britain, Turkey and Gulf Arab states have already recognised the coalition as the legitimate representative of the Syrian people. The United States has been more cautious.

Hijab is a Sunni Muslim from the desert oil-producing province of Deir al-Zor in the east of Syria, on the border with Iraq's Sunni heartland.

Alliances in Deir al-Zor between Sunni Muslim tribes and the ruling elite from Assad's minority Alawite sect, an offshoot of Shi'ite Islam that has dominated power in Syria since the 1960s, collapsed after Assad's forces shot scores of demonstrators in the province at the beginning of the revolt. – Reuters