Next of kin refers to the closest living relative of the deceased. In Australia, this typically includes a person's spouse, de facto partner, or nearest blood relative. This designation is commonly used in estate planning documents such as a Last Will & Testament.

While Australia lacks an official legal definition of next of kin, various state and territory legislations offer guidance on determining the most senior next of kin. The hierarchy is as follows:

• Spouse or domestic partner
• Adult son or daughter (eldest surviving takes seniority)
• Parent
• Adult sibling
• Person named in the Will as an executor
• Person who, immediately before the death, was a personal representative of the deceased person
• Person determined by the Coroner based on the closeness of the relationship with the deceased person before their death.

In instances where a Last Will & Testament nominates an executor, that individual assumes responsibility for the deceased's estate. If no valid Will exists (dying intestate), the next of kin typically takes on this role.

• Applying for a grant of Probate if there is no Will or executor.
• Decision-making on organ donation and post-mortem examinations (if applicable).
• Notification of family and friends of the death.
• Death registration within 30 days.
• Funeral arrangements.
• Resolution of financial affairs.
• Administering the deceased's estate, including asset valuation and distribution to beneficiaries.

It's crucial to note that assuming responsibility for estate administration is not a legal obligation for the next of kin.