Umno deputy president Muhyiddin Yassin said the decision to sack Gopeng Umno Wanita chief Hamidah Osman went against the spirit of the party constitution.
He said this in reference to the Umno supreme council's decision to dismiss Hamidah on Tuesday, which was announced by party president Najib Abdul Razak.
"If it is true that Hamidah was never called before the disciplinary board to defend herself, then her sacking clearly goes against the spirit of the Umno constitution.
"Also, the sacking of members under Article 20.9 of the Umno constitution should be the last option, whereby members have committed a major offence which contravened the Umno constitution and ethics," he said in a statement tonight.
Muhyiddin noted that there were arguments that the Umno supreme council could sack members without going through the disciplinary board as it was the case when then Umno deputy president Anwar Ibrahim was sacked in 1998.
"These people (who make such arguments) do not know history. the disciplinary board was only created through an amendment to the Umno constitution in 2000, two years after Anwar was sacked," he said.
Muhyiddin said it was he who had cleared the committee to amend Umno's constitution then.
Muhyiddin added that it was he who had proposed for the creation of the disciplinary board comprising of members without any interest, to ensure all decisions are made fairly, transparently, and without fear or favour.
After Hamidah's sacking, she had revealed that she was given a show-cause letter for welcoming back former Umno president Dr Mahathir Mohamad at Subang International Airport.
Mahathir is Najib's fiercest critic and has vowed to unseat him.
Muhyiddin questioned if the reason given was sufficient ground to sack Hamidah.
"I would like to ask, is attending a function with the former Umno president, which is also attended by many other Umno leaders, a disciplinary offence?
"If it is a disciplinary offence, then many more Umno members will be sacked and Umno will become a party that keeps losing members and supporters," he said.
Hamidah was one of seven leaders on Umno's watch list.
Also on the watch list were believed to be Muhyiddin himself and Umno vice-president Shafie Apdal.
However, both leaders were spared in the Tuesday meeting as some Umno supreme council members feared their sacking would cause further cleavage within the party.
Muhyiddin and Shafie were dismissed from the government in July for their critical stance against Najib's handling of 1MDB.