Zaid Ibrahim believes that Muhyiddin Yassin is not the best choice to replace Prime Minister Najib Abdul Razak if the latter steps down.

The former law minister said the current number two is unlikely to reform the country and undo what Najib has done in the past few years.

"Will he bring the 1MDB (1Malaysia Development Berhad) issue to a close with full disclosure to the rakyat and punish the offenders no matter who they are? I think that's also unlikely.

"This is why I believe that if Mahathir wants better and more accountable leaders for Umno in the years to come - and at the same time put an end to systemic corruption and improve the quality of the public institutions - the choice of successor must be none other than Tengku Razaleigh Hamzah," he added in a blog post.

Tengku Razaleigh, who is popularly known as Ku Li, like Mahathir, is an Umno veteran.

The former finance minister had once mounted a challenge against Mahathir for the Umno presidency in 1987, which was the impetus for a new chapter in Malaysian politics.

Zaid also said Muhyiddin would remain neutral as Mahathir continues to hammer Najib and wait until the prime minister's "train has well and truly gone off the rails."

"The results of the upcoming by-elections will be instrumental.

"We'll have to look at the results in Rompin and Permatang Pauh: if Umno does not do well, then it will be all the more pressing for Mahathir to openly name Najib's successor," he added.

'Change the train, not just the driver'

Should Mahathir propose Tengku Razaleigh, said Zaid, the public would see him making an effort to institute reforms for Umno instead of just changing the leader.

"(It should not be) just seeking to replace the train driver with someone more suited to his liking, but rather to change the train itself, which is more suited to the needs of the country.

"The broad appeal that Mahathir enjoys today with the rakyat can be put to full effect if there is a sign that he wants Umno as a whole to change, and not just its leader," he added.

He believed that Tengku Razaleigh would have a positive impact on Malaysia because he has the necessary qualities.

Firstly, Zaid said Tengku Razaleigh, a former finance minister, is capable of understanding the economic hardships of ordinary Malaysians and would likely increase the minimum wage and other schemes to encourage entrepreneurship.

"Tengku Razaleigh is a friend to ordinary Malaysians, unlike Umno leaders in Putrajaya today who are friends only with tycoons and big businesses," said Zaid.

Secondly, Zaid ( right ) believed Tengku Razaleigh is capable of fostering better ties between ethnic groups and even encourage opposition parties to join hands in nation building.

"More importantly, he can bring to the government a new standard by which leaders are judged.

"He himself is not afraid of being judged and examined, and does not need the Official Secrets Act and the Sedition Act to 'protect' him from any wrongdoings," he said.