The operation was instigated following the Tampa affair in September 2001 and the Australian government's resultant Pacific Solution.
The focus of Operation Relex was illegal immigration, with assets from all three services of the ADF deployed to prevent the arrival of Suspected Illegal Entry Vessels (SIEVs) in the Australian migration zone.
The primary period of activity of Operation Relex was between October and December 2001 when ten SIEVs were intercepted by HMA Ships Warramunga, Arunta, and Leeuwin, assisted by several Fremantle-class patrol boats.
In 2013, the Abbott government implemented Operation Sovereign Borders.
The Australian Government issued a medal for service on Border Protection on 22 May 2012.