Prime Minister Najib Abdul Razak today told ex-premier Dr Mahathir Mohamad that he was no longer helming the country and thus should not take centre stage.

The premier said this when delivering the keynote address at the World Capital Markets Symposium in Kuala Lumpur. He was responding to master of ceremonies Riz Khan's earlier anecdote about his (Khan's) wife.

"I was never in my wife's wildest dream," Riz had said.

"Thank you for the very amusing remark about a certain lady," Najib then told the 500-strong crowd.

"I want to paraphrase in my own context. Never in my wildest dreams did I imagine that one of my predecessors would be against me in this manner," he said, but without naming his antagonist.

He then asked the country's longest-serving prime minister to cease and desist.

"He is no longer the prime minister and should not take centre stage," he quipped, drawing laughter from the audience.

Mahathir has been criticising Najib's brainchild 1MDB since last September and has even urged Najib to step down.

He even came out with a formula for the opposition to join hands with BN lawmakers to topple Najib through a vote of no confidence.

Mahathir had also turned up at the Bersih 4 rally to call for people's power to oust Najib.

The police have said they will quiz Mahathir for attending the rally.

IGP Khalid Abu Bakar ( photo ) has also disclosed the former premier will be investigated for criminal defamation on remarks he made during Bersih 4.

Related reports

Rally Behind Mahathir or live with Najib

Economic committee's first task is ask PM to leave

Nur Jazlan claims Amanah's vehicle not a political party

'France optimistic M'sia will buy Rafale warplanes'

'Malaysian' in tourism posters, 'Chinese' in rallies

Why target vernacular schools when it's more multi-racial?

Umno man urges counter to 'Chinese' Bersih rally

DAP: Liow dancing to Umno's 'racist' tune

Five things we may have forgotten post-Bersih 4

An eventful three months, but will Najib get the message?

Khairuddin roasts IGP for going after Dr M but not PM

PM to Dr M: Get off the national centre stage

My open letter to Low and IACC delegates

Expelled Wanita Umno leader can hold her head high

MCA grassroots reportedly unhappy Liow too soft in BN

On cue, Umno plays race card in wake of Bersih 4

Haze worsens, 12 areas declared 'unhealthy'

Three weeks later, AG 'still studying' 1MDB probe report

At least 1pct of the citizens attended Bersih 4