An Umno Supreme Council member has slammed Amanah for questioning the royal pardon bid for jailed former leader Najib Razak, in the latest war of words among the ruling parties comprising the coalition government led by Anwar Ibrahim.

Puad Zarkashi, who is also the Johor state speaker, said Amanah's call on the Yang di-Pertuan Agong not to grant a pardon to the former prime minister was not only insulting to the monarch, but also showed the Pakatan Harapan (PH) component party as a "difficult", double-faced friend.

"This is why it's hard to be friends with PAN," Puad said, using the initials shunned by supporters of the PAS splinter party, who prefer the abbreviation "Amanah" (trust).

"(We) can only be friends. A friend who does not guarantee that the unity government can remain. A friend who betrays a friend."

Puad, who has similarly slammed DAP's Lim Kit Siang for protesting the pardon bid, said Amanah could not be a comrade for Umno to any extent further than a "political friend".

"The party led by Mohamad Sabu should be called PAN instead of Amanah," he added.

His remarks appear set to fuel the rising tension between ruling parties in the PH coalition headed by Anwar, and the Umno-dominated Barisan Nasional whose support for the PKR president last year made him the country's 10th prime minister following a hung parliament after the general election.

On Friday, Amanah criticised Umno's efforts to free Najib, who is serving a 12-year sentence at Kajang Prison for his conviction in the SRC International case.

Amanah spokesman Khalid Samad said a pardon for Najib would send a negative message to the people, the country's justice system and the entire world about Malaysia's attitude towards corruption and abuse of power.

"Will giving a pardon to someone who has embarrassed the country on a global scale show a firm and uncompromising stand towards corruption? Surely not," Khalid had said.

The statement drew a sharp response from Umno president and Deputy Prime Minister Ahmad Zahid Hamidi, who urged all quarters to stop commenting on the application for a royal pardon.

It also prompted Kelantan Umno, set to become allies with Amanah in their bid to capture the PAS-held state at the coming polls, to demand a public apology from Khalid, a request the Amanah leader has refused.

Puad's statement came after fellow Umno Supreme Council leader Nur Jazlan Mohamed lashed out at PH leaders for suggesting that the Malay party was latching on to the coalition for its own survival following its worst electoral defeat ever at the polls last year.

Jazlan shot back by saying that DAP was a liability to the coalition government in its efforts to win back Malay support.

"They depended on Chinese-majority seats and mixed seats to win 80 seats at GE15," he said.

Former prime minister Ismail Sabri Yaakob has also joined the growing dissent within Umno, describing Umno's current cooperation with PH as a "forced marriage" amid tit-for-tat comments between DAP and PKR leaders.