Since Syria's war broke out in 2011, neighbouring Türkiye has taken in more than three million people who fled the fighting.
The construction site Soylu visited was formerly an airstrip.
On a billboard, "Project for safe, voluntary and honourable returns" was written in Arabic and Turkish, while the names of organisations including Türkiye's relief agency AFAD and the Qatar Fund for Development featured on the sign.
"Qatari emir (Sheikh Tamim bin Hamad) Al-Thani and our President Recep Tayyip Erdoğan have taken a big step toward addressing one of the world's most important issues," Soylu said, according to the IHA report.
"To date, there have been 554,000 voluntary returns," Soylu said. "There is a serious demand for a voluntary and dignified return to this safe area."
Earlier this month, Erdoğan pledged to build some 200,000 homes in 13 locations in Syria, aiming to resettle some one million refugees, local media reported.