The original basis for Syria's suspension from the Arab League over a decade ago still stands, Qatar's prime minister, Sheikh Mohammed bin Abdurahman Al-Thani, said in a television interview on Thursday.
Al-Thani said Qatar maintains its stance on normalization with Syria unless there is a political solution to the crisis.
Arab nations are preparing to meet in Saudi Arabia to discuss rehabilitating Assad.
Riyadh withdrew its ambassador from Damascus in 2011 and severed diplomatic ties with the Assad regime, following its deadly crackdown on pro-democracy protests.
The Syrian regime, however, began to exchange official visits and contacts with several Arab countries in recent months amid reports about a possible resumption of Syria's membership in the Cairo-based Arab League.
Friday's nine-nation talks in Jeddah, the Red Sea gateway to Mecca, come after Syria's foreign minister arrived on a previously unannounced visit – the first since the outbreak of the country's civil war in 2011.
It was one in a flurry of events that were nearly unthinkable before Saudi Arabia and Iran's landmark, Chinese-brokered announcement on March 10 that they would resume ties, seven years after an acrimonious split.
On Wednesday, an Iranian delegation landed in Saudi Arabia to pave the way for reopening diplomatic missions, following a trip by a Saudi team in the opposite direction.
The Saudi ambassador to Yemen has held talks with Iran-backed Houthi rebels this week aimed at ending the devastating civil war that has raged since a Saudi-led military intervention started in 2015.
Earlier this month, the Saudi and Iranian foreign ministers pledged to work together to bring "security and stability" to the troubled region during a meeting in Beijing.
And late on Wednesday, gas-rich Qatar and its tiny Gulf neighbor Bahrain agreed to re-establish relations, putting aside a long-running diplomatic feud.
Saudi Arabia, the world's biggest oil exporter, and Iran have long been vying for influence around the region, with Yemen a major battleground.
But analysts say Saudi Arabia is now trying to calm the region to allow it to focus on domestic projects aimed at diversifying its energy-dependent economy.