In rem is Latin for “related to a thing”. In contrast to an action in personam, an action in rem is a proprietary action brought against the object that is the subject of a dispute. The determined rights adjudicated as a result of an action in rem are conclusive against the whole world (i.e. persons claiming an interest in the property at any time), rather than merely between two parties to a dispute.
Actions in rem are prevalent in the sphere of admiralty law. Actions in rem will occur if proceedings are commenced against a ship, and in Australia, if the claim falls within the scope of the Admiralty Act 1988 (Cth), a party can have a ship arrested so that a claim can be determined. Actions in rem, in terms of admiralty law, are heard in the Federal Court and are commenced through the issue of a writ upon a ship (the ship as the proper defendant as opposed to its captain) whilst it is within Australia waters. It is then at this point that a claim against the ship is determined and it is either sold or released from arrest.