The 58 MPs from Jacob Zuma's MK party have taken their oaths at the National Assembly, ten days after the official ceremony.
Though they still dispute the election results, they have decided to join the opposition as a broad national unity government is being formed.
Opponents of President Ramaphosa, including Duduzile Zuma, daughter of former President Jacob Zuma, and former judge John Hlophe, have now taken their seats. Despite the MK party's aim to abolish the Constitution, its MPs swore to uphold it. John Hlophe, now the opposition leader, emphasized, "We are not hooligans."
The MK is expected to ally with Julius Malema's Economic Freedom Fighters (EFF), totaling 100 seats.
This is small compared to the government coalition forming, which holds over two-thirds of the 400 seats. However, the coalition has yet to form a government a week after President Cyril Ramaphosa's inauguration, a sign of potential instability that the opposition hopes will lead to a quick collapse.