President Cyril Ramaphosa could more than halve his cabinet by firing "compromised" ministers, South Africa's opposition leader, Mmusi Maimane said.

Participating in the debate on Ramaphosa's state-of-the-nation address, the leader of the Democratic Alliance, the biggest opposition party in the country, welcomed his stated commitment to reducing the size of Cabinet.

"At 35 ministries, each with a deputy minister, ours one of the most bloated governments in the world," said Maimane.

"It is entirely possible to cut our executive down to 15 ministries, with spending priorities that promote economic growth and job creation. This would save us around R4.7-billion each year."

He said ministers embroiled in allegations of state capture and other scandals should get the chop first.

"Show South Africa you are really serious about fighting corruption in your party and fire Bathabile Dlamini, Faith Muthambi, Mosebenzi Zwane, Malusi Gigaba, Des van Rooyen, David Mahlobo, Lynne Brown and Bongani Bongo," said Maimane.

An end to cadre deployment at all levels of government and the State must be prioritised. This, said Maimane, meant getting rid of people appointed to key positions, including Public Protector Busisiwe Mkhwebane and National Director of Public Prosecutions Shaun Abrahams.

"It was deployed cadres who hollowed out our state owned enterprises to enrich a few individuals close to the former president. And it was cadres deployed to the commanding heights of the criminal justice system – the NPA, the Hawks and SARS – who looked the other way."