Former prime minister Dr Mahathir Mohamad, who is currently undergoing treatment at the National Heart Institute (IJN) for chest infection, is recuperating well.

IJN's corporate communication department, in a statement, said Mahathir continued to respond well to treatment.

"Apart from physiotherapy, Mahathir is also being put through routine physical exercise and doctors are happy with his progress," the statement said.

Mahathir, 91, is currently admitted to the general ward and based on the medical team's advice, visitation is strictly for close family members only, it said.

In 1989, he suffered heart problems and underwent coronary bypass surgery at the IJN.

Mahathir underwent a second bypass operation in 2007. In 2013, he was admitted to the IJN for 10 days for treatment of a chest infection.

- Bernama