SIEV Augustus was a vessel carrying 20 smuggled migrants from Sri Lanka which took on water and ultimately sank, approximately 80 kilometres northwest of Christmas Island on 19 July 1999. Five passengers were rescued by a private yacht. A search and rescue mission by Australian authorities later found one further dead body, leaving 14 persons missing. No prosecution followed this incident.

The vessel referred to as SIEV Augustus by Australian authorities left Sri Lanka carrying a number of smuggled migrants and was accompanied by another vessel. A statement by the then Minister for Immigration, Mr Philip Ruddock, further revealed that: 'At a predetermined point, the crew on the boat carrying the Sri Lankans transferred to the accompanying boat and returned to Indonesia, leaving the Sri Lankans stranded.'

Sometime later, the engine of SIEV Augustus failed, leaving those on board to drift and bail water. Three or four days later, on 19 July 1999, the Augustus sank in rough seas. Five survivors were discovered and rescued by a yacht 80 kilometres northwest of Christmas Island. At that point, the five survivors had spent about eight hours in the water.

Australia's Search and Rescue Centre launched a search for the remaining passengers, but recovered only one dead body, leaving 14 passengers missing.