"They (the opposition) are trying to gain political advantage through baseless distortions even about the health condition of our president. Our president is on duty with great strength, health, and vigor," Communications Director Fahrettin Altun told an event in Istanbul.
The nation stands with its leader, who works with "inexhaustible" effort, he added.
Vice President Fuat Oktay said Erdoğan was doing well, state news agency Anadolu reported. "We are in constant contact. He has caught a little cold."
Speculation about Erdoğan's health mounted earlier on Wednesday after he cancelled the day's scheduled election campaign rallies due to a "minor sickness."
"I will rest at home today as our doctors advised," Erdoğan wrote on Twitter, citing health problems he suffered a day before.
Erdoğan was scheduled to attend campaign speeches in three separate central Anatolian provinces on Wednesday.
Late on Tuesday, Erdoğan had to briefly cut a live television interview after he suffered what he later described as stomach upset.
The president later returned to finish the interview, where he said an intense election campaign led to some "serious" stomach troubles. Erdoğan said he considered cancelling the interview ahead of time.
The joint opposition candidate for president, Kemal Kılıçdaroğlu, separately wished Erdoğan a speedy recovery on Twitter.
