“There is not an iota of evidence where Zanu PF or I, as President, has ever expressed the violation of our Constitution,” the 81-year-old said.
“We in Zanu PF are very democratic and we obey the Constitution.”
Zanu PF, the ruling party has reigned over Zimbabwe since independence.
The party secured a supermajority in Parliament last February in disputed by-elections.
This left it closer to changing the constitution if it wishes.
Zimbabwe’s 2013 Constitution limits the presidential term of office to two five-year mandates and establishes a constitutional court.
A supporter of a hard line and heavyweight of the party in power (Zanu-PF) since independence, Mnangagwa became head of state at the end of a war of succession which opposed him to Grace Mugabe, the wife of president Robert Mugabe who was dismissed in 2017.