Dr Mahathir Mohamad was admitted to the National Heart Institute (IJN) early this morning for treatment of a chest infection, his aide Sufi Yusoff said.

mahathir ikmal presidential lecture 290410 The former prime minister was admitted to the normal ward at about 6am after having developed fever and cough over the last two days, he said in a statement.

"Dr Mahathir is currently undergoing intravenous antibiotic treatment and intensive chest physiotherapy," he said.

Speaking to AFP, Sufi said Mahathir was "feeling ill" earlier this morning, which led to his admission to the IJN.

Around noon, his condition was stable and "he is presently resting", said he added.

"Doctors say that he has a chest infection and he is expected to be in hospital for about a week," he added.

Dr Mahathir, 85, who is president of the Perdana Global Peace Foundation, is expected to remain at the institute for about a week.

Sufi said doctors had advised the former prime minister against receiving visitors except close family members.

In a tweet this afternoon, Mahathir's son Mukhriz also said his father "is resting & recovering from cough at IJN."

"Heart is ok. It's rice, prawn curry, fried chicken & long beans for lunch. No visitors pls," said Mukhriz.

- Agencies