Yildirim’s remarks came during an interview on state-run broadcaster TRT.
"We think that the president will be elected for a five-year term in (the presidential) system," Yildirim said.
Constitutional changes, in particular, the call for a presidential system, has been on the political agenda since Recep Tayyip Erdogan, the former prime minister and current AK Party leader, was elected president in August 2014.
That election was the first in which a Turkish president was chosen directly by popular vote.
Yildirim praised the leader of Turkey’s opposition Nationalist Movement Party (MHP) for his support of a referendum on a proposed presidential system.
"Mr. Devlet Bahceli sometimes makes this kind of breakthrough. This breakthrough opens every time the doors for the solution of a country’s issues becomes an insolvable issue."
Bahceli has called for a referendum to settle the debate on Turkey’s Constitution and presidential system.
"The MHP is on the side of the continuation of [Turkey’s] parliamentary system while it is revised and reformed,” he said earlier this week.
Yildirim also commented on the parliamentary election in the new Constitution, saying deputies could also be elected to five-year terms.
"We have not got inside the content, but we think that the parliamentary elections should be for five-year terms."