Benetton Treviso replied with a 62nd minute try from winger Ludovico Nitoglia but by then the result never in doubt.
Mike Sherry scored Munster's fifth and final try just before the final whistle.
Man of the match David Wallace after the win "We had a good attitude tonight, all things worked well for us and our set piece gave the backs a platform to work from. Everyone who came on made a huge impact, and that's what we ask for across the 23."
Munster: Scott Deasy; Doug Howlett, Keith Earls, Johne Murphy, Denis Hurley; Ronan O'Gara, Peter Stringer; Wian du Preez, Damien Varley, John Hayes; Mick O'Driscoll, Donnacha Ryan; Alan Quinlan, David Wallace, James Coughlan. Replacements: Mick Sherry, Darragh Hurley, Tony Buckley, Donncha O'Callaghan, Peter O'Mahony, Duncan Williams, Paul Warwick, Ivan Dineen.
Benetton Treviso: Brendan Williams; Ludovico Nitoglia, Ezio Galon, Andrew Vilk, Benjamin De Jager; Kristopher Burton, Fabio Semenzato; Franco Sbaraglini, Leonardo Ghiraldini capt, Ignacio Fernandez Rouyet; Enrico Pavanello, Valerio Bernabò; Francesco Minto, Benjamin Vermaak, Robert Barbieri. Replacements: Enrico Ceccato, Augusto Allori, Pedro Di Santo, Antonio Pavanello, Marco Filippucci, Tommaso Benvenuti, Tobias Botes, Simon Picone.
Referee: David Jones (WRU).