Provided you can prove a de facto relationship of at least 12 months your partner may be an eligible family member and become a secondary applicant on your student visa.
Importantly, however “eligible family members” (a partner and partner’s dependent children) may only be added to your student visa where their existence has been disclosed in your student visa application. A partner may therefore be added to your student visa, but only if you disclosed your relationship at the time of your application or the relationship commenced after your student visa was granted.
If you were in a relationship at the time of your student visa application but you did not disclose this to the Dept. of Immigration, you may not add that partner after the grant of the student visa.
In that case you would need to apply for a new student visa and include your partner in the new application, providing such also met the various criteria outlined below.
If you did disclose the existence of a partner at your initial application, then you may add your partner later if you also meet the criteria below.
The criteria discussed above are as follows:
The student visa applicant/holder must be in assessment level 1 or 2 OR
Eligible for streamlined visa processing OR
In assessment level 3 or 4 and the course is longer than 12 months.
Note: If the duration of the course is less than 52 weeks, your family members are eligible to join you in Australia if your current course(s) has a total duration of 52 weeks or more, or you have been in Australia lawfully for 12 months or more. Assessment levels are determined by your course of study and your nationality.