Officials from Zimbabwe's ruling party have downplayed Julius Malema's "Grandpa it's enough" criticism of longtime president, Robert Mugabe.

"Not bothered at all by Julius Malema's latest ranting," said Psychology Maziwisa, a Zanu-PF Member of Parliament who has worked in the party's information department.

"He is a little and irrelevant man who is trying desperately to gain political mileage in South Africa by insulting a great man in Zimbabwe. Won't win!" Maziwisa posted to Facebook.

But Malema's dig at ruling party "cowards" who he said had not been able to advise Mugabe to go will have shaken some in the president's party.

The Economic Freedom Fighter leader used to be outspoken in his praise of the now-nearly-93-year-old leader. Just 18 months ago, Zimbabwe's main opposition Movement for Democratic Change spokesperson Obert Gutu said Malema's over-the-top adulation of Mugabe showed he had an "unsound" mind.

Asked what he thought of Malema's comments, Higher Education Minister Jonathan Moyo was non-committal. "I think Malema will always be Malema while everything else is obladi oblada as life goes on!" Moyo tweeted, adding that he was preoccupied by Zimbabwe's AFCON match against Tunisia on Monday evening.

This isn't the first time Malema has told Mugabe his time is up: in December the red berets' commander-in-chief said that although "we love Robert Mugabe for who he is... we accept it's time for him to step down," News24 reported.