Without mentioning his name, Prime Minister Najib Abdul Razak launched a broadside against his former mentor-turned-nemesis Dr Mahathir Mohamad.

Najib noted how, during Mahathir's tenure, the former prime minister too was subjected to various allegations, including being labelled as "kepala perompak" (head of thieves).

"Whatever accusations were thrown at him during his time, the infrastructure development continued and the country went through the transformation process despite the political foes, with whom he collaborates now, accusing him of corruption and abuse of power," he said.

Therefore, Najib said, there is no difference between what he is experiencing now and what Mahathir went through during his time in office.

"I will continue my work to develop the religion, race and this beloved nation despite all the accusations he (Mahathir) has hurled against me.

"The people need a leader who can serve them full time and not with the objective of toppling someone else," he added in a blog post today.

Najib on why he joined politics

Najib said he had joined politics via Umno to uphold race, religion and the country, which is in tandem with his values and objectives.

However, he said, it was disappointing that a veteran leader is now willing to pawn such ideals and work with those whose aims are in direct contradiction with Umno.

"It is common knowledge, he has never been defeated and to save face, he is willing to do anything to avoid failure in the effort to topple the existing government.

"Just to defend his ego, he consistently hurls all sorts of allegations against me and my administration. But what he claims reek of slander and is blown out of proportion," he added.

On Wednesday, Mahathir, who has been hospitalised for chest infection, challenged Najib to a televised debate about governance in Malaysia, following the latter’s remarks accusing him of trying to boss the prime minister around.

"I am old now. But Allah be praised, I am not senile. I will gladly accept an open debate with Najib with live audience and on live telecast. The debate should be on governing a country.

"I may lose. Cash may win. It is for Malaysians to evaluate, not TV3 or the NST or my own known supporters," the 91-year-old former prime minister said in his blog post.