Senior African National Congress MP Dennis Bloem is expected to be unveiled on Friday as a member of COPE - but was still insisting on Thursday that he remained a loyal member of the ANC.
Bloem sparked controversy this week when his name appeared on candidate lists for both the ruling party and COPE.
The Mercury was reliably informed on Thursday that COPE would officially announce Bloem's defection at a media briefing at its Johannesburg offices today.
Bloem refused to comment on Thursday.
ANC secretary-general Gwede Mantashe said the party would not tolerate a member's name appearing on the list of an opposition party and said Bloem's name would be removed from the ANC's list.
Ironically, Bloem was in the relatively safe 125th spot on the ANC list. COPE, which has yet to prove its electoral strength in the pending national and provincial elections, has placed him at number 30, statistically a far less secure position.
COPE spokesperson Sipho Ngwema said on Thursday night he was unaware that a press conference had been planned to announce Bloem's defection.
However, he confirmed that Bloem was an official candidate for election to Parliament.
ANC spokesperson Jessie Duarte said the party had written to the electoral commission for verification of the identity of the "D Bloem" who featured on the COPE list.
If he remains in the ANC Bloem may face disciplinary proceedings.
If he does move to COPE, he will join other former ANC MPs who feature prominently on the new party's list. They include Kiki Rwexane who is at number eight on the list, correctional services committee member Bishop Lekoba Tolo (14), Mampe Ramotsomai (17) and Bloem's Free State homeboy Lewele Modisenyane (37).