The Syrian conflict is at a "turning point" with regime forces gaining ground, the French foreign ministry said Tuesday, adding that it was time to review whether to arm the opposition.

President Bashar al-Assad's regime has pledged to focus its attention on the northern city of Aleppo after winning a strategic victory by retaking Qusayr, a strategically important town on the border with Lebanon.

"There are lessons to be drawn from what happened in Qusayr and what is happening in Aleppo," said ministry spokesman Philippe Lalliot.

"We are at a turning point in the Syrian war. What should we do under these conditions to reinforce the opposition armed forces? We have had these discussions with our partners, with the Americans, the Saudis, the Turks, many others...

"We cannot leave the opposition in the current state," he said.

Lalliot said a French official will on Saturday meet Salim Idriss, the chief of staff of the Free Syrian Army's Supreme Military Council.

The European Union, under pressure from Britain and France, last month failed to renew an arms embargo on Syria, leaving individual member states free from August 1 to supply weapons to the opposition, if they so decided.

Lalliot said no decision to deliver arms had been taken but the issue would be discussed and reviewed after the fall of Qusayr.

The United States and Russia are trying to organise a peace conference bringing together Assad's regime and the rebels in a bid to end the fighting that has claimed 94,000 lives since March 2011.

Amid wrangling between opposition leaders and a fierce debate over who should attend, the date for the talks initially slated for May has now slipped back to July at the earliest.

Lalliot said he did not believe it was a good time for the planned meeting given the weakening of the opposition's position in the face of the regime's military gains.