It was the first time a Turkish statesman had indicated a serious setback in the deployment plan, although the statement did not spell out whether the president thought troops would ultimately be sent or not.
"For me this question is closed," Sezer said on Wednesday at a reception marking the 80th anniversary of the founding of the Turkish republic.
The United States originally asked Ankara for military help in Iraq, but then appeared to back-pedal on the idea in the face of opposition from Iraq's governing council.
"For me this question is closed"
Ahmad Necdet Sezer
"It is very difficult to reconcile the necessary conditions for deploying troops," Sezer was quoted as saying.
Turkey's parliament three weeks ago voted in favour of the deployment, despite widespread public opposition with about 80% of the public against dispatching soldiers.
On Tuesday, Turkish Foreign Minister Abd Allah Gul accused the US of ineptly handling the issue.
"We are not going to undertake anything as long as there are hesitations... everything concerning us should be very clear, everybody should say yes," Gul said.
Faced with opposition from Iraq's interim leadership, the US has stopped pushing for the Turkish troops.
Many Turkish politicians, including ministers, have expressed relief at the prospect of shelving the deployment plan, which has also come under fire from fellow Muslim nations.