You’re facing a discrepancy between your initial student visa application (where you declared only 8 siblings) and your current situation (where you now wish to invite an elder sister whose name was not included). Here’s how you can address this under Australian immigration law and policy:\n\n---\n\n### **1. Legal Framework Under the Migration Act/Regulations**\nThere is no specific provision in the **Migration Act 1958** or **Migration Regulations 1994** that penalizes inadvertent omissions in family details on a previous visa application, provided there was no fraudulent intent. However, consistency in declarations is important for assessing credibility.\n\nKey points:\n- **Section 101** of the Migration Act requires visa applications to be \"correct\" but focuses on **material** misrepresentations (e.g., hiding a dependent or spouse). Omitting a sibling is unlikely to be deemed material unless it was deliberate deception.\n- **Regulation 2.07** allows for updates to personal details via **Form 1022 (Notification of changes in circumstances)**, but this applies mainly to changes *after* visa grant (e.g., new dependents). Your sister’s existence predates your application, so this form may not apply.\n\n---\n\n### **2. Steps to Resolve the Issue**\n#### **A. Proactively Correct the Record**\n- **Write to the Department of Home Affairs (DOHA)**: Submit a voluntary statement via the [ImmiAccount](https://immi.homeaffairs.gov.au/) portal or by email (to the address where you lodged your original application). Explain:\n - The omission was unintentional (e.g., due to misunderstanding the form or family complexity).\n - Provide evidence of your sibling relationship (see below).\n - Clarify that this does not affect your current visa status (as siblings are not \"dependents\" for visa purposes).\n\n#### **B. Evidence to Prove Sibling Relationship**\nWhen inviting your sister (Visitor Visa subclass 600), include:\n1. **Statutory Declaration (Form 888)**: Sworn statements from you and other family members confirming the relationship.\n2. **Birth Certificates**: Showing shared parents (translated/notarized if not in English).\n3. **Family Photos/Communication Records**: Evidence of ongoing contact (e.g., messages, family events).\n4. **Affidavits from Relatives**: If birth records are unavailable, affidavits from parents or older siblings may help.\n5. **DNA Testing (if requested)**: DOHA rarely mandates DNA tests for visitor visas, but they may request it if doubts arise. You can preemptively offer this if other evidence is weak.\n\n#### **C. Visitor Visa Application (Subclass 600)**\n- In her application, your sister should:\n - Declare you as her sibling and explain the omission in your student visa application.\n - Provide the above evidence.\n - Emphasize her **genuine temporary entrant (GTE)** status (ties to home country, return ticket, etc.).\n\n---\n\n### **3. Will Immigration Question the Omission?**\n- **Unlikely to affect her visa**: Visitor visas are assessed on the applicant’s circumstances, not minor inconsistencies in *your* past forms.\n- **No formal \"update\" mechanism**: Since siblings are not material to most visas (unlike spouses/dependents), DOHA does not require retroactive updates for non-dependent relatives. Focus on proving the relationship for her visitor visa.\n\n---\n\n### **4. Key Takeaways**\n- **No penalty for honest mistakes**: If the omission was unintentional, it won’t impact your PR status or her visa chances.\n- **Document the relationship**: Prioritize birth certificates and statutory declarations.\n- **Transparency is key**: Address the discrepancy upfront in her visa application (e.g., a cover letter explaining the oversight).\n\nIf DOHA raises concerns, you may seek advice from a registered migration agent (MARA) to navigate complex cases. However, your situation is manageable with proper documentation. \n\nFor official guidance, refer to DOHA’s [Family Visitor Visa page](https://immi.homeaffairs.gov.au/visas/getting-a-visa/visa-listing/visitor-600/family-sponsored-stream).