Fifty-eight MPs from Dr John Hlophe's Umkhonto we Sizwe (MK) party will be sworn in as Members of Parliament this morning.
They had told Parliament just over a week ago that they would not be able to be sworn in alongside other elected officials.
At the time, the party said it would contest the results of the May 29 election.
The MK Party did not attend the mass oath-taking ceremony held in Parliament on June 14 and 15.
To serve as a member of Congress, one must take an oath or affirm allegiance to the Republic and obedience to the Constitution.
Ahead of the election, President Jacob Zuma, the party's leader and one of its founders, had indicated his intention to amend the constitution if he came to power.
The party has meanwhile indicated that impeached former judge John Hlophe will become its leader in parliament.
Corruption accused Zizi Kodwa from the African National Congress (ANC) parliament is also reportedly due to be sworn in.
It is unclear whether the retirement rules apply to Kodwa as a member of parliament.
Opening of Parliament
As the country waits for President Cyril Ramaphosa to announce his cabinet, Parliament has said its speakers will consult with President Ramaphosa on the date for parliament to sit.
The joint meeting will be held at the Cape Town International Conference Centre, but a date and time has yet to be decided.
Parliament is scheduled to hold various meetings this week to set up the structure of the seventh government.
The rules committees of the National Assembly and National Council of State Legislatures are scheduled to meet on Wednesday.
Video: MK members take oath on Tuesday:
