"Parliament is mandated by the Constitution to hold the executive accountable. For this reason, the DA has today requested that National Assembly Speaker, Baleka Mbete, establish an ad-hoc committee to fully probe the relations of captured ministers, the president and the Gupta family."
Maimane said the request would require a debate in the National Assembly, where the opposition hoped that ANC MPs would "put South Africa first" and support setting up such the committee.
He said allegations of collusion with the Gupta family needed to be investigated against Finance Minister Malusi Gigaba, Public Enterprises Minister Lynne Brown, Mineral Resources Minister Mosebenzi Zwane and Local Government Minister Des van Rooyen, in particular.
Commenting on reports that Zuma at the weekend had again survived an attempt by members of the ANC's National Executive Committee (NEC) to remove him from power, Maimane said this proved that the ruling party was not able to alter course.
But he said the opposition had been encouraged by the will ANC MPs had shown in recent weeks to probe mounting allegations of officials giving the Gupta family access to the state's coffers.
"What happened at the weekend might only encourage this, because it has now become clear that the NEC cannot remove Jacob Zuma, so if anything this might make the appetite here increase because Parliament is the ultimate vehicle for holding the executive to account."
He added that he was concerned that the oft-used term state capture had become a euphemism. "It is grand corruption and theft at the highest levels. It is a mafia state."