GENEVA: A Syrian official says President Bashar Assad's government will "never accept" the removal of two militant groups from a list of terrorist organisations barred from peace talks.

Ahrar al-Sham and the Army of Islam, two Islamic groups fighting to overthrow Assad, agreed to take part in UN-sponsored peace talks in Geneva.

But the Syrian government and its close ally Russia view both as terrorist groups that should be excluded from the process, along with the Islamic State group and al-Qaida's local affiliate.

Information Minister Omar al-Zoubi's comments to state TV late Saturday came as the main opposition delegation arrived in Geneva.

The delegation has named Army of Islam official Mohammed Alloush as its chief negotiator.

Most parties agree that IS and the al-Qaida-affiliated Nusra Front should be excluded.