* More than 30 members of coalition threaten to resign
* Decision postponed to one week before scheduled talks
By Dasha Afanasieva
ISTANBUL, Jan 7 (Reuters) - Syria's Western-backed opposition in exile postponed until next week a decision on whether to attend talks with President Bashar al-Assad's government aimed at ending nearly three years of devastating conflict, opposition members said on Tuesday.
The National Coalition is facing heavy pressure from Western powers to attend the Jan. 22 talks, seen as the most serious effort yet to find a political solution to Syria's civil war.
It has said it is ready to attend the talks in principle, but says they must lead to Assad's departure - a demand which Damascus has flatly rejected - and has repeatedly stalled on its final decision.
The latest delay came after at least a quarter of the coalition called for its newly re-elected president Ahmad al-Jarba to stand down, and threatened to resign if their demand was not met, sources at the meeting said.
Saudi-backed Jarba beat former Syrian prime minister Riyad Hijab, who defected nearly 18 months ago, to win a second term as president of the coalition.
Amid high tensions and reports of physical fights, more than 30 of the coalition's 121 members were threatening to resign at a closed meeting in a resort town on the Black Sea on Tuesday, with around four resignations officially accepted, senior members said.
The members from groups such as the Supreme Military Council, the military wing of the coalition, and local councils which have stronger links on the ground than most of the opposition in exile, demanded greater representation and a re-run of the presidential election without Jarba.
The dissenters were persuaded to hold off formally submitting their resignation by officials from the Friends of Syria group, an alliance of nations mostly opposed to Assad, at a meeting in Istanbul on Tuesday, members said.
They said the vote on attending the peace talks in Switzerland would be held after an international meeting of the 11-strong core group of the Friends of Syria in Paris on Jan. 12, just a week before the scheduled talks in Montreux, Switzerland.
"First we would like to hear from the next meeting of the Core 11 group in Paris to make an informed decision," senior coalition member Anas Abdah told Reuters.
"Secondly, due to the problem that we had with a few of around 30 of our colleagues leaving the meeting and threatening to leave the coalition, we thought it would not be appropriate to make such an important decision without everyone present."
Jarba's chief of staff Monzer Akbik on Tuesday said the coalition election had been fair and transparent and gave Jarba a clear majority. (Editing by Dominic Evans and Mike Collett-White)