Former prime minister Dr Mahathir Mohamad has regained consciousness at 3.30pm today and is recovering in intensive care today after his second heart bypass surgery in 18 years.

Mahathir was now able to talk, Mirzan Mahathir told the national news agency Bernama .

The 82-year-old former leader was admitted to Kuala Lumpur's National Heart Institute on Sunday after suffering two heart attacks in the past year.

He spent about five hours on the operating table yesterday.

"Doctors are happy with his rate of progress, which is as expected in post-bypass surgery," the institute had earlier said.

"Mahathir is still, however, within the crucial intensive observation period and will continue to be warded at the ICU (Intensive Care Unit)."

Another son Mukhriz Mahathir urged Malaysians to pray for his father's recovery.

"This recovery phase is a lifeline for dad, because anything can happen during this time. So we need to pray harder and give special care and attention for him to pass this second test," he said.

Earlier Mahathir was given 48 hours by his doctors to regain consciousness following his surgery yesterday, stating that he was still in a critical stage after undergoing the five-hour surgery at the heart hospital.

Mukhriz, who is Mahathir's fifth child, had earlier today said that the attention was now on the second phase - the post-surgery part - of his father's recovery.

He added that the family hoped this stage would go smoothly and safely.

"The doctors said my father's situation is stable and that his heartbeat and pulse are normal," he added.

Under observation in ICU

Meanwhile, Prime Minister Abdullah Ahmad Badawi and his new wife, Jeanne Abdullah, were at the institute this afternoon to visit Mahathir.

They arrived 90 minutes after Mahathir regained consciousness. However, they did not get to see him as only close family members were allowed in, said Dr Mahathir's son, Mokhzani.

IJN, in a statement, said that Mahathir was recovering in intensive care today.

"Mahathir remains stable following close overnight observation by doctors and nurses at the Intensive Care Unit of IJN," said the hospital.

"All his vital parameters, thus far, are also stable as anticipated," the institute said.

Yesterday the hospital said that Mahathir would be kept sedated overnight.

Mukhriz also said that his mother Dr Siti Hasmah Mohamad Ali was very thankful to all Malaysians for their prayers and well wishes that his surgery would go smoothly.

He added that the former first lady was deeply touched by the SMS messages and e-mails of support the family received from Malaysians of all walks of life.

"She was so delighted when I showed her the SMSes and e-mails," he said. "Our family is very thankful to everyone for their concern."

First bypass in 1989

Mahathir underwent his first coronary bypass operation on Jan 24, 1989 at the Kuala Lumpur Hospital.

Mahathir, who ruled Malaysia for more than two decades, was admitted to the IJN for elective surgery on Sunday after suffering two heart attacks in the past year.

He last appeared in public on Friday, waving the Malaysian flag as part of the country's celebrations marking 50 years since independence from Britain.

Mahathir led Malaysia for 22 years before handing power to the current premier Abdullah Ahmad Badawi in 2003.