Dr Mahathir, who has been in power for 22 years, shocked his party when he announced his immediate retirement last June. He later agreed that he would delay stepping down.

The prime minister said in a statement issued on Monday that his deputy, and the designated future leader, Abdullah Ahmad Badawi, would assume his responsibilities while he was away.

Dr Mahathir's holiday destinations will include "several countries in the Far East and South America," a senior government official was quoted as saying by the Associated Press news agency.

It will allow him to take time out from a busy schedule, which included hosting the 116-nation Non-Aligned Movement summit last week.

He flew on Tuesday to Doha, Qatar, for an emergency meeting of the Organisation of the Islamic Conference, before he begins his travels.

His two months away will give Mr Badawi a chance to practise being leader, and the country time to get accustomed to his different style.

While Dr Mahathir is well-known across the region as an outspoken firebrand, correspondents say Mr Badawi, 63, is a far more softly spoken figure.