I have scored 46% in B.Com and 52% in M.Com ,can I eligibility for MBA in Australia.

Criteria depends on university to university. But good universities require atleast 60-70 percent.

for good college you need minimum 60%

All good universities require first division I.e atleast 60% in Bachelor's. You may try the average business schools or score high in GMAT, TOEFL/IELTS to get admission. Work experience also matters. Alternatively, a PG diploma is the best way. Take a look at imperial.edu.au