The criticism levelled against former Umno president Najib Abdul Razak is a manifestation of the party's disappointment with his successor Ahmad Zahid Hamidi, Zainuddin Maidin said.
In his blog posting today, the former information minister, who is better known as Zam, said Umno leaders were not pleased with Najib overshadowing Zahid.
"The criticism also reflects the disappointment of Umno leaders towards Zahid, who allowed himself to be overshadowed by Najib and (this) shows his continued dependence on Najib.
"Several known Umno leaders are no longer comfortable with Zahid's weak leadership," Zam added.
Zahid took over as acting president following Najib's resignation after the May 9 general election. He was officially elected as Umno president in the party elections in June.
Over the past two days, Najib has become the target of intense criticism from Umno leaders after he campaigned for BN's candidate Lokman Noor Adam in the recently-concluded Sungai Kandis by-election.
Among them included former minister Johari Abdul Gani, who stated that Najib's era as president was "history" and he should not have been allowed to campaign.
Following this, Umno secretary-general Annuar Musa reportedly said Najib was a "baggage" the party could no longer afford to carry and it should not waste time defending him.
However, Annuar later claimed that his remarks were taken out of context.
Zahid then came to Najib's defence, urging his former boss not to take to heart these comments and urged those in Umno not to trample on a man who is down.
Yesterday, Umno vice-president Khaled Noordin said Umno cannot reform if it continued to allow Najib to play a significant role.
Khaleed also said that it is the former president on trial, not Umno.
Najib, who was re-elected as Pekan Umno division chief, said there was no need for Umno to defend him and explained that he campaigned in Sungai Kandis because the candidate requested him to do so.