LONDON (REUTERS) - Britain will use its role as host of a summit of the Group of 8 (G-8) industrialised nations next week to try to get both sides in the Syrian conflict to attend a peace conference, Prime Minister David Cameron said on Wednesday.

"We should use the G-8 to try and bring pressure on all sides to bring about... a peace conference, a peace process, and a move towards a transitional government in Syria," Mr Cameron told Parliament.

Russian President Vladimir Putin would fly to London on Sunday for advance talks about Syria before the summit in Northern Ireland, he added.

British Foreign Secretary William Hague said on Sunday he was worried and depressed by the lack of progress on convening the peace conference in Geneva.

Pressed repeatedly on the subject, Mr Cameron stressed that Britain had not taken any decision to supply arms to Syrian opposition forces fighting to topple President Bashar al-Assad.

"We are not supplying the opposition with weapons. We are supplying them with technical assistance and non-lethal equipment," he said. "We have made no decision to supply the opposition with weapons."