Countries opposed to Syrian President Bashar al-Assad's regime are to recognise the newly-formed opposition coalition as "the legitimate representative" of the Syrian people, a statement obtained by AFP showed.

"The participants acknowledged the National Coalition as the legitimate representative of the Syrian people and the umbrella organisation under which Syrian opposition groups are gathering," said the statement to be approved by a meeting of the Friends of Syria group in Morocco on Wednesday.

The meeting in the southern city of Marrakesh has brought together representatives of more than 100 countries for talks on the 21-month conflict rocking Syria.

It comes just a day after US President Barack Obama endorsed the opposition group as the legitimate representative of the Syrian people.

British Foreign Secretary William Hague described the growing recognition of the National Coalition as "real progress."

"Then the important thing is to channel more assistance through them -- in our case ... non-lethal assistance... and then of course we need more humanitarian aid," Hague told reporters before the start of the meeting.

Under pressure to unite, the Syrian opposition agreed in Doha on November 11 to establish the National Coalition and group the various rebel forces under a supreme military council.

But jihadist rebels in Aleppo, a key front line in northern Syria, rejected the coalition, saying they want an Islamic state.

Among them was the Al-Nusra Front, which the United States blacklisted on Tuesday as a "terrorist" organisation, citing its Al-Qaeda links.