Erdogan's comments reflect a shift in stance at a time when he is rebuking Western leaders for their response to the July 15 coup bid. Erdogan vowed to keep Turkey's promises on the migrant deal as recently as July 26.
"The European Union is not behaving in a sincere manner with Turkey," Erdogan said in comments published by Le Monde on Monday, noting that the visa waiver for Turkish citizens was supposed to kick in on June 1, Reuters reported.
"If our demands are not satisfied then the readmissions will no longer be possible," Erdogan said.
Ankara agreed in March to stop migrants from crossing into Greece in exchange for financial aid being revived, the promise of visa-free travel to much of the EU and accelerated membership talks.
However, the reciprocal visa-free access has been delayed due to a dispute over Turkish anti-terrorism legislation and concern in the West about the scale of Ankara's crackdown following a failed coup.
Criticizing the response of Washington and European leaders to the attempted putsch, Erdogan said the Turkish people had been abandoned by the West.
"The whole world reacted to the attack against Charlie Hebdo. Our prime minister joined a rally in the streets of Paris," Erdogan said, referring to the deadly militant attack on the office of the French satirical magazine in January 2015.
"I would have hoped that the leaders of the Western world would have reacted (to the coup attempt) in the same way and not have contented themselves with a few clichés."
In Berlin on Monday, a spokeswoman for the German foreign ministry repeated that reinstatement of the death penalty in Turkey would end its bid to join the EU.
Erdogan, speaking to German television station ARD last month after the coup attempt, said the Turkish people wanted the death penalty bringing back and those governing the country should listen to them.