Former acting CEO Jimi Matthews was "the biggest coward ever" for not speaking out while still working at South African Broadcasting Corporation (SABC), the Communication Workers Union (CWU) said on Tuesday.

CWU president Clyde Mervin said Matthews should have raised questions while he was still working at SABC, not once he had jumped ship.

"When he was working at SABC, he defended them, but now he is complaining. It can’t be correct," Mervin said.

Matthews resigned last week under a cloud as the uproar at the public broadcaster continued.

In his resignation letter, Matthews said COO Hlaudi Motsoeneng had fostered a climate of censorship and political pandering at the SABC, resulting in the suspension of several journalists.

"If he had any issues with the SABC he could have come to us, but he never said anything. He went to go look for public stance," Mervin said.

Addressing media outside their offices in Smit Street, Braamfontein, Mervin told journalists that Motsoeneng was not bigger than the board and the executive committee.

"We are not defenders, but if he is doing something wrong we will go for his head," Mervin said.

The CWU would always be against any censorship by any person or institutions and would continue to fight for freedom of the press, the union's general secretary, Aubrey Tshabalala, said.