Madhevere has played in 98 matches across all formats for Zimbabwe, his last a Twenty20 against Ireland on December 10th.
Mavuta featured in the last of his 26 internationals in a one-dayer against the same opponents on Sunday.
"Zimbabwe Cricket has with immediate effect suspended two Zimbabwe international players from all cricket activities, pending a hearing, for allegedly breaching anti-doping rules," ZC said in a statement.
"The concerned players, Wessly Madhevere and Brandon Mavuta, both tested positive for a banned recreational drug in an out-of-competition case recorded during a recent in-house doping test."
The suspensions came a day after coach Dave Houghton resigned from his position ahead of a white-ball tour to Sri Lanka in January.