Charles Milupi, the independent parliamentarian for Luena in Western province on Friday resigned as MP to form his own political party, Alliance for Democracy and Development (ADD).
Milupi ended months of speculations and denying that he is about to form a political party.
The PF-UPND pact has already predicted victory in the bye-election to come.
United Party for National Development (UPND) spokesperson Charles Kakoma has been quoted saying Milupi has a democratic right to form a party but that the people of Zambia already belong to the PF-UPND pact.
He said the pact will contest the Luena seat and are assured of victory.
But Milupi, who grabbed the seat from the UPND in 2006, says he will defend the seat on his new party.
The MMD last held the Luena constituency in 1991, when their candidate Mubukwanu Kunyanda polled 6,261 to beat Chrispin Sibeta of UNIP who got 937.
Chrispin Sibeta later wrestled the seat from MMD and defended it under UPND until Milupi got it in 2006.
Milupi hold an Honors Degree in Electrical and Electronics Engineering