Former Malaysian premier Dr Mahathir Mohamad, who is recovering from heart bypass surgery, has gone back into intensive care just a day after being moved into a normal ward, the hospital said today.

However, his spokesman Sufi Yusoff said that 82-year-old Mahathir's condition had not deteriorated, and that the move was merely to facilitate the normal monitoring process.

"The reason is that they need to do X-rays and continue monitoring. They can't do it in the normal ward," he told AFP.

The National Heart Institute said Mahathir was transferred to the intensive care unit last night.

"This is to allow for doctors to conduct investigations and close observation of his overall condition post bypass surgery," it said in a statement.

Continued monitoring

It said Mahathir was in a stable condition but was "expected to remain in ICU for continued monitoring".

Mahathir underwent the five-hour operation on September 4 after suffering two heart attacks within a year. He previously had bypass surgery in 1989.

The former leader resigned in 2003 after 22 years in power, handing the reins over to the current prime minister, Abdullah Ahmad Badawi.

Despite retiring from office, Mahathir remains an influential figure and has become an outspoken critic of his successor, accusing him of economic mismanagement, nepotism and corruption.