The tripartite alliance needed to unite and close ranks against the “enemy”, South African Communist Party general secretary, Blade Nzimande, said on Sunday.

"Look at what is happening in Brazil. They want to remove the president outside the democratic processes," Nzimande told a few thousand people at a Congress of South African Trade Unions’ May Day rally in Mamelodi.

He was referring to efforts to impeach Brazilian president Dilma Rousseff by that country’s conservative opposition.

"We must maintain unity. Let us close rank. Let us consolidate and accelerate the second phase of the national democratic revolution."

President Jacob Zuma has survived several attempts by opposition parties in Parliament to remove him as president, including a vote of no confidence in April.

The motion came after the Constitutional Court ruled Zuma had failed to uphold the Constitution when he failed to comply with Public Protector Thuli Madonsela's remedial action regarding the non-security upgrades to his Nkandla homestead.

Nzimande said the ANC-Cosatu-SACP alliance needed peace.

"The enemy attacks us when we are not united. We must be united at all times. There are comrades who say we should not fight because we are going to elections.

"Does that mean we will start beating each other up once the elections pass? We should have unity at all times," he said, to loud cheers from the crowd.