Lungu announced this week that he was prepared to stand for re-election.
“I am eligible to stand in 2021 and if you want you can go to the Constitutional Court and they will tell you I am eligible to stand in 2021,” Lungu told supporters in the central Copperbelt province on Thursday.
“God willing and if the people allow I will stand,” he added.
His declaration has sparked debate among Zambians on his eligibility. The constitution allows a president two five-year terms.
Lungu came into power in 2015 to complete president Michael Sata’s five-year tenure after Sata had died in October 2014 — two years before completing his term.
Lungu was re-elected last August, narrowly beating Hakainde Hichilema, head of the opposition United Party for National Development (UPND).
The opposition party argues that Lungu is ineligible to stand again in 2021.
“Lungu does not qualify… We can’t continue with a dictator, his police are killing people every day,” UPND lawmaker Douglas Syakalima, an adviser to Hichilema, told AFP on Saturday.
“Who in Zambia would want to continue with a tin-pot dictator? His election is still been challenged but he is already talking about 2021,” he added.
However in Luapula province on Saturday Lungu’s Patriotic Front (PF) party endorsed his candidacy for the 2021 election.
Political analyst Alex Ng’oma, of the University of Zambia, said that the current constitution allows Lungu to seek another five-year mandate.
“The portion of Sata’s tenure that Lungu served is less than three years so he is eligible to stand. But the party has to follow democratic channels to arrive at who becomes their candidate,” Ng’oma told AFP on Saturday.
Lungu’s bid for re-election is hampered by divisions within the ruling party, emanating from his sacking of information minister Chishimba Kambwili in November.
Kambwili is seen by many as a potential presidential candidate in 2021.