“I have not seen him (Assad) approach reforms with a democratic understanding,” Erdogan told reporters in the capital, Ankara, on Sunday.
The Turkish prime minister also stated that President Assad is taking “an autocratic approach” to the issues inside Syria.
“I believe that it is very hard to achieve peace in Syria as long as this approach continues.”
Over the past few months, Turkey, Saudi Arabia and Qatar have expressed support for arming the anti-Damascus rebels inside Syria.
Turkish Foreign Minister Ahmet Davutoglu said on March 4 that Ankara supports supplying arms to rebels in Syria fighting against the Assad government.
Meanwhile, Assad said on Sunday that the May 7 parliamentary elections in Syria served as a response to the “criminal killers and those who finance them.”
The Syrian president made the remarks in an address to the newly-elected parliament in Damascus.
The May 7 elections were part of the reforms promised by President Assad.
More than half of the eligible voters in Syria participated in the elections, which were held under a new constitution that paved the way for a multiparty system in the country.
About 90 percent of Syrian voters approved the new constitution in a referendum held on February 26.
Separately, Turkey and a number of Western countries have announced the expulsion of senior Syrian diplomats in an apparently coordinated move to protest the May 25 massacre in the western Syrian town of Houla which left more than 100 people, including women and children, dead.
Some Western governments blame Damascus for the massacre, but a Syrian government investigation into the deadly incident has shown that anti-Damascus armed groups had carried out the killings to “bring foreign military intervention against the country in any form and way.”