Zimbabwe's National Assembly Speaker Jacob Mudenda has reportedly said that the ongoing debates within the ruling Zanu-PF party about President Robert Mugabe's "potential" successor are "premature" and "taboo".

According to NewsDay, Mudenda said this on the sidelines of the ruling ANC's 105 birthday celebrations in Soweto on Sunday.

Mudenda said that the debates over Mugabe's successor were a sign of a "lack of discipline and unbridled ambition". He added: "No new sun rises before the old one sets."

He said that Zanu-PF party members were not supposed to openly display their ambitions to succeed the nonagenarian leader.

Mugabe, who was set to turn 93 in February, has ruled the southern African country since independence in 1980.

"It is a complex one, but my belief is that no new sun rises before the old one sets. There must be an element of discipline within the party so that the system itself produces a leader, who should succeed the leadership. It [succession] must be looked in a holistic manner," Mudenda was quoted as saying.

More controversy

"We must also avoid political ambitions where we allow the system to dictate who should succeed [Mugabe]."

Reports indicated that Zanu-PF was riddled with factional fights.

Two "powerful" warring factions were reportedly gunning support to take over from Mugabe once he left or died in office.

A group of young Turks known as the generation 40 (G40) allegedly led by Mugabe's wife Grace was against the possible rise of Vice President Emmerson Mnangagwa to the hotly contested seat.

Mnangagwa was said to be backed by top military bosses as well as the country's 1970s war veterans.

The vice president recently appeared in a picture on social media, in which he held a coffee mug inscribed "I am the boss", a development that led some to accuse of trying to topple Mugabe.

Minister of Higher Education Jonathan Moyo quickly took to his Twitter account to lambast Mnanngagwa.

Numerous presents

"...Everybody knows that the Boss is Gushungo (Mugabe). One Boss at a time, please! Kumhanya hakusi kusvika veduwe (There is no need to rush).

Mnangwagwa, however, rubbished the insinuations that he wanted to take over from his boss, saying in a statement, that there were individuals within Zanu-PF who sought to cause tension between him and Mugabe.

State media said that the mug was part of the numerous presents that Mnangagwa received from Christmas and "took to his rural home unopened".

But, according to reports over the weekend, it had since emerged that the vice president in fact held an event at his home village in Zvishavane, where he hosted at least "two dozen activists who were either suspended or expelled by Zanu-PF".

Some unnamed commanders from the security forces were also in attendance at the party.

A source close to the development was quoted as saying that the "secret" meeting now dubbed the "Mug-declaration" was called to "coronate Mnangagwa as the new boss in Zanu-PF, who will succeed President Mugabe".