No solution proposed at Syria peace talks next month will be implemented without President Bashar al-Assad's approval, the deputy foreign minister said in remarks published Sunday.

"The Syrian (government) delegation at Geneva will be working under Assad's directives, and any solutions proposed will have no impact unless Assad approves of them," Faisal Muqdad said in remarks in the Syrian press.

He lashed out at Western calls for Assad to step down, saying the president "represents Syria's sovereignty and unity".

The US-Russian peace initiative dubbed Geneva 2, which should bring government and rebel representatives to the negotiating table in a bid to end the bloody 32-month war, is being planned for January 22.

The opposition has agreed to attend the talks on condition that they lead to a transitional phase that excludes Assad and his regime.

But government officials and their backers in Iran and Russia insist there should be no preconditions, and Assad has also said he would be willing to stand for re-election in 2014.

The proposed talks come amid rising international fears of an Islamist takeover in Syria.

According to Muqdad, "in their closed meetings, Western leaders say there is no replacement for Assad".

He also said that at Geneva 2, "we will gather around the table and we will discuss, without foreign interference... and there will be an enlarged government".

Muqdad reiterated his government's "reservations about participation (in Geneva 2) by representatives of the armed terrorist groups," the government term for rebels.

He also said opposition backer Turkey "has started to change its policy" on Syria.

Once an Assad ally, Ankara became the lead voice calling for regime change after Damascus cracked down on peaceful protests that later morphed into a bloody insurgency.

More recently, the rise of jihadism in Syria has made Turkey more cautious on the conflict raging across its southern border.

Muqdad criticised "the stupid Turkish policy which has compromised the Turkish people... by attracting Al-Qaeda" to its territory.

According to Ankara, 500 Turks have joined jihadist ranks in Syria.

Last week, a Turkish delegation led by Foreign Minister Ahmet Davutoglu visited Assad's main regional backer Iran. The Turkish and Iranian diplomatic chiefs both said they would press for a ceasefire ahead of Geneva 2.