The minimum requirements for admission to a PhD program are:

a bachelor degree requiring at least four years of full-time study in a relevant discipline awarded with honours. The degree should include a research component comprised of a thesis, other research projects or research methodology courses that constitute at least 25% of a full-time academic year (or part-time equivalent). The applicant must have achieved at least a distinction average in the final year; or
a master degree that includes a research component comprised of at least 25% of a full-time academic year (or part-time equivalent) with an overall distinction average or a master degree without a research component with at least a high distinction average; or
evidence of appropriate academic qualifications and/or experience that satisfies the Associate Deputy Vice-Chancellor, Research Training and Development or nominee that the applicant has developed knowledge of the field of study or cognate field and the potential for research sufficient to undertake the proposed program.

At RMIT a grade of distinction represents academic achievement of 70% or higher and a high distinction is 80% or higher.

To study this program you will need to complete one of the following English proficiency tests:

IELTS (Academic): minimum overall band of 6.5 (with no individual band below 6.0)
TOEFL (Internet Based Test - IBT): minimum overall score of 79 (with minimum of 13 in Reading, 12 in Listening, 18 in Speaking and 21 in Writing)
Pearson Test of English (Academic) (PTE (A)): minimum score of 58 (with no communication band less than 50)
Cambridge English: Advanced (CAE): minimum of 176 with no less than 169 in any component.