Prime Minister Najib Abdul Razak has described Pakatan Harapan's leadership line-up as "farcical" and likened it to the puppet show “Punch and Judy”.

Speaking at InvestMalaysia 2017, he also said the line-up would not inspire confidence in the economy.

Najib claimed that the federal opposition is now in chaos, citing as an example the dispute on whether the alliance between PKR and PAS still stands in Selangor.

"It's like a Punch and Judy show!

"And the latest leadership structure the opposition announced is farcical, sounding a bit like a return to work programme for old-age political pensioners," he added.

Harapan had recently named former prime minister Dr Mahathir Mohamad as its new chairperson, as part of the requirements to register its four component parties as one formal coalition.

Mahathir had also said he believes he is Harapan's "top dog" and its unofficial equivalent to Najib.

Aside from Mahathir, Harapan had also announced jailed PKR de facto leader Anwar Ibrahim and PKR president Dr Wan Azizah Wan Ismail as the coalition's de facto leader and president respectively.

Commenting further, Najib described the structure as being "cynical and deceptive" with three leaders but no clarity on who among them would have the executive powers.

"As for their prime minister candidate, the opposition is so desperate they are now trying to make the people believe it will be a nonagenarian - who isn't even a member of parliament, and whose party has just one seat!" said Najib.

Najib did not mention any names but his remarks were clearly directed towards 92-year-old Mahathir as Parti Pribumi Bersatu Malaysia chairperson. Bersatu holds the Pagoh parliament seat via its president Muhyiddin Yassin.

"But the truth is that in a democracy numbers don't lie, and DAP remains, by far, the most dominant party in the opposition.

"The DAP leader of the last half century is now hiding behind the man who jailed him, trying to deceive Malays into thinking that the former leader is their interim candidate for prime minister," he said, believed to be a reference to DAP's parliamentary leader Lim Kit Siang who was arrested during Ops Lalang in 1987 during Mahathir's tenure as prime minister.

Since the announcement of Harapan's new line-up, Lim had said that Najib as well as other BN ministers were trapped in a contradiction between claiming DAP leaders were the puppet-masters in Harapan and alleging that DAP leaders had been sidelined and marginalised.

He also insisted that the DAP did not nominate him to be a part of Harapan's leadership in order to make way for more youths.