Lim Kit Siang unleashed a feline cannonade on MCA deputy president Wee Ka Siong, whom he accused of dancing to Umno's tune with regard to the Penang undersea tunnel scandal.
Describing him as "Umno's catspaw", the DAP veteran claimed Wee's actions were aimed at staining and tarnishing the Penang Pakatan Harapan's reputation for integrity and good governance.
He also claimed that the agenda behind this is to make the 1MDB scandal appear less "monstrous".
"Wee... (is) trying to strike a posture of a great anti-corruption fighter but who is afraid to breathe a single word about Najib's (Prime Minister Najib Abdul Razak) 1MDB scandal," he said.
The MCA leader has repeatedly dared Lim's son and Penang chief minister Guan Eng to a public debate on the tunnel issue, which is the subject of a MACC probe.
Guan Eng, however, has refused to entertain the dare.
BN leaders on the other hand have questioned their Harapan counterparts' silence on the tunnel issue.
Meanwhile, Lim also claimed if Wee had the "guts and gumption" of the sacked Pahang MCA division leader David Choi, he would not behave in this manner.
MCA had stripped Choi of all party positions for apologising to a farmer arrested for sharing a video deemed insulting to deputy minister Chong Sin Woon, following the latter's "deity" jibe after the Penang floods.
Lim claimed that if all of MCA's national leaders possessed a fraction of Choi's traits, they would dare to speak up on the rights and wrongs in the country and the party would not have been reduced to the "ridiculous state of a 7/11 party".
The "7/11" remark refers to MCA being left with only seven parliament seats and 11 state seats following the 2013 general election. DAP, on the other hand, won 38 parliament seats.
The DAP veteran said MCA leaders must not allow themselves to be pushed around by Umno.
"If the MCA president, deputy president and secretary-general have a fraction of the guts and gumption of Choi, and not hide in predominantly Malay-majority seats to depend basically on Umno's Malay votes to get into parliament and cabinet, they would have long spoken out about 1MDB which has reduced Malaysia into a global kleptocracy," he added.