Recep Tayyip Erdoğan, a former football player and an avid Fenerbahçe supporter, said he backed a thorough and fair investigation and prosecution.
"I am not only a Fenerbahçe fan, I am a member of its congress," Erdoğan told reporters. "(But) if there was abuse or wrongdoing, this has to be brought to light in a fair manner."
"I hope that it is concluded quickly and fairly so that our (image) internationally is not blemished," he said.
Turkish police conducted raids to homes and club premises, detaining some 60 people suspected of manipulating games in the Turkish league last season, making it the latest country to be affected by a slew of match-fixing and betting scandals.
The Turkish police chief's office said in a statement Wednesday that investigators had obtained evidence of cheating and bribery involving 19 first and second-division games. Police had also seized eight unlicensed guns during the sweep and had evidence that some players were threatened into forfeiting money owed to them, the statement said.
Those detained this week include several club officials and players as well as the president of Fenerbahçe, whom newspaper reports say is suspected of bribing rival teams' players to play badly. Police and court officials have not commented on the investigation.
Prosecutors on Wednesday questioned 25 of the suspects, the state-run Anatolia news agency reported. Seven other suspects were formally arrested after questioning Tuesday while 11 were released from jail.