Zambia's President Levy Mwanawasa has warned the opposition leader that he could be charged with treason.
Michael Sata is a long-time opponent of the president
Michael Sata has said he would run a parallel government in areas such as the capital, Lusaka and the Copperbelt, that elected opposition councils.
"Let him not push his luck too far, I will sort him out," Mr Mwanawasa said.
Mr Sata has said he was cheated of victory in last month's elections and his supporters staged violent protests, after Mr Mwanawasa's victory.
Mr Mwanawasa was speaking as he named his first cabinet following the 28 September elections.
His new vice-president is Rupiah Banda, 69, a businessman who was Zambia's first foreign minister after independence.
Mr Banda replaces Lupando Mwape, who lost his parliamentary seat in the Northern Province.
"The people of Northern Province... want to be in the opposition... and therefore I have taken away the vice-presidency from them," Mr Mwanawasa said.
The president reappointed his finance and energy ministers, Ngandu Magande and Felix Mutata.
The new foreign minister is Mundia Sikatana and defence minister is George Mpombo.
Mr Mwanawasa, who has pledged to tackle graft, also said he planned to disband a task force on corruption because of its "dismal performance" in recovering stolen public funds, reports the Reuters news agency.
He has been accused of using the fight against corruption to pursue a witch-hunt against his political rivals, including his predecessor Frederick Chiluba.