Inkatha Freedom Party leader Mangosuthu Buthelezi has sought to allay supporters' fears that he will leave politics because of ill health.

He said such concerns had been conveyed to him during his five-day hospital stay.

Buthelezi, 83, was admitted to the Empangeni Garden Clinic, north of Durban, suffering from fatigue.

"I can assure all those who expressed such concern that it takes much more than a scratch to get Mangosuthu Buthelezi off the battlefield," he wrote in his online newsletter on Friday.

He said he was grateful for having been spared serious illnesses in his life.

"I have always worked to the fullest measure my body and mind have allowed, and often beyond."

Buthelezi said he had been admitted to hospital because he had pushed himself too far.

"I was forced to go to hospital on account of being overworked and extremely fatigued.

"I thank God for it, though, considering that most people do not make it to my age and many of those who do are not able to work long hours."

His forced break had given him time to watch national discourse much more closely, he said.

"I am particularly concerned about the fissures between our different ... groups that are being forced open by careless statements and reckless behaviour."

Buthelezi criticised the ANC for rejecting the Equality Court's ruling that the singing of "Shoot the Boer" constituted hate speech.