The Democratic Alliance says it will ask the Public Service Commission (PSC) to probe the apparent unlawful appointment of fisheries department deputy director general Greta Apelgren-Narkedien.
This comes after Apelgren-Narkedien allegedly admitted in a television programme that no formal procedures were followed when she took office.
The alleged television show was aired on Carte Blanche on March 24.
Fisheries Minister Tina Joemat-Pettersson had since denied the appointment was irregular.
"Minister Joemat-Pettersson alleged that Ms Apelgren-Narkedien had been appointed by President Jacob Zuma via a presidential minute," said DA Member of Parliament Pieter Van Dalen.
The DA wanted the PSC to investigate the exact version of events which led to the appointment.
"If the deputy director general was not appointed via formal procedures, she must be relieved of her duties and the appropriate steps must be followed to ensure and maintain the highest levels of integrity in the public service," said Van Dalen, adding that the appointment was another example of nepotism and cadre deployment.
Apelgren-Narkedien was a member of the ANC's armed wing Umkhonto we Sizwe (MK).