It's better to do MS Mechanical courses from USA, But If you're interested in Australia you can also opt for australia for further studies.

Here is the list of Top USA Universities for MS Mechanical Engineering course

Massachusetts Inst Of Technology CAMBRIDGE
Stanford University STANFORD
University Of Michigan Ann Arbor
Univ Of Illinois At Urbana-Champaign URBANA
University Of California-Berkeley BERKELEY
California Institute Technology PASADENA
Princeton University PRINCETON
Cornell University ITHACA
University Of Texas At Austin AUSTIN
University Of Minnesota MINNEAPOLIS
Univ Of California-San Diego San Diego
Pennsylvania State University University Park
Northwestern University EVANSTON
Georgia Institute Of Technology ATLANTA
Univ Of California-Los Angeles Los Angeles
Rensselaer Polytechnic Inst TROY
Texas A&m University College Station
Purdue University West Lafayette
Carnegie Mellon University PITTSBURGH
Brown University PROVIDENCE
Virginia Polytech Inst & State U BLACKSBURG
North Carolina State University RALEIGH
University Of Wisconsin-Madison MADISON
University Of Pennsylvania PHILADELPHIA
Ohio State University COLUMBUS
Case Western Reserve Univ CLEVELAND
University Of California-Davis DAVIS
Columbia University New York
Lehigh University BETHLEHEM
Michigan State University East Lansing
Rice University HOUSTON
University Of Arizona TUCSON
University Of Maryland College Park College Park
University Of Washington SEATTLE
University Of Southern California Los Angeles
University Of Notre Dame Notre Dame
Rutgers State Univ-New Brunswick New Brunswick
Oklahoma State University STILLWATER
University Of Delaware NEWARK
Duke University DURHAM