Earlier, the justice, crime prevention, and security (JCPS) cluster of ministries said it was responsible for securing the parliamentary precinct.
This followed disruption of proceedings in the National Assembly by Economic Freedom Fighters MPs on Thursday.
DA Chief Whip John Steenhuisen said the executive was overstepping the mark.
“At this morning’s briefing, the chairperson of the cluster, [Defence Minister] Nosiviwe Mapisa-Nqakula, said the fracas in the House last week constituted a threat to national security, and that the executive ‘cannot stand idle as our democracy is undermined’,” Steenhuisen said.
“This is a veiled threat, which completely ignores Parliament’s responsibility to uphold its own rules and therefore handle this matter.”
The opposition party would write to the parliamentary oversight authority (POA) for an urgent meeting.
“The POA must send a very clear message to members of the executive that this infringement of its powers and independence as a separate arm of the state will not be accepted,” said Steenhuisen.
“It is high time that Parliament tells the executive to back off and take its oversight role seriously.”
In the JCPS briefing, Mapisa-Nqakula and Police Minister Nathi Nhleko denied there was an attempt to breach the separation of powers, insisting police were responsible for security at Parliament.
According to their interpretation, the executive commanded the police and therefore had every right to intervene.
Mapisa-Nqakula said the law provided for police officers to help eject errant MPs from Parliament as soon as the Speaker or chair of the House ordered it.
“The Speaker… decided that the sergeant-at-arms should come in and escort the members out of the House, and when there was resistance to that, immediately all of us should have known that by the Speaker saying ‘sergeant-at-arms remove’… what it means is that your protection security services can come in and assist with the escorting of people out.”
Mapisa-Nqakula blamed the police’s failure to act on confusion about the rules.
She cited both section 59 of the Constitution, which regulates, among others, the removal of people from the National Assembly, and section 11 of the legislation governing parliamentary powers.
“[The] Powers, Privileges, and Immunities of Parliament and Provincial Legislatures Act of 2004, section 11, provides for: if there is a person who creates or takes part in any disturbance in the precinct while Parliament, or the House or a committee is meeting, may be arrested and removed from the precinct on the order of the Speaker, or the chairperson, or a person designated by the Speaker or chairperson, by a staff member or a member of the security service.”
Thursday’s chaos erupted after EFF leader Julius Malema and his fellow MPs expressed unhappiness about how President Jacob Zuma had answered questions on when he was going to repay part of the R246 million spent on security upgrades to his private Nkandla residence in KwaZulu-Natal.
Public Protector Thuli Madonsela had recommended in her report on Nkandla, titled “Secure in Comfort”, that Zuma repay that part of the money not spent on security measures, like the swimming pool and cattle kraal.
Zuma has been accused of delaying responding in Parliament to Madonsela’s report after he said he would leave it to Nhleko to determine if he should repay any of the money.