Aims In this paper we outline and evaluate competing explanations for a heroin shortage that occurred in Australia during 2001 with an abrupt onset at the beginning of 2001.

Methods We evaluated each of the explanations offered for the shortage against evidence from a variety of sources: government reports, police and drug law enforcement documents and briefings, key informant (KI) interviews, indicator data and research data.

Results No similar shortage occurred at the same time in other markets (e.g. Vancouver, Canada or Hong Kong) whose heroin originated in the same countries as Australia’s. The shortage was due most probably to a combination of factors that operated synergistically and sequentially. The heroin market had grown rapidly in the late 1990s, perhaps helped by a decline in drug law enforcement (DLE) in Australia in the early 1990s that facilitated high-level heroin suppliers in Asia to establish large-scale importation heroin networks into Australia. This led to an increase in the availability of heroin, increasingly visible street-based drug markets, increased purity and decreased price of heroin around the country. The Australian heroin market was well established by the late 1990s, but it had a low profit margin with high heroin purity, and a lower price than ever before. The surge in heroin problems led to increased funding of the Australian Federal Police and Customs as part of the National Illicit Drug Strategy in 1998–99, with the result that a number of key individuals and large seizures occurred during 1999–2000, probably increasing the risks of large-scale importation. The combination of low profits and increased success of law enforcement may have reduced the dependability of key suppliers of heroin to Australia at a time when seized heroin was becoming more difficult to replace because of reduced supplies in the Golden Triangle. These factors may have reduced the attractiveness of Australia as a destination for heroin trafficking.

Conclusions The Australian heroin shortage in 2001 was due probably to a combination of factors that included increased effectiveness of law enforcement efforts to disrupt networks bringing large shipments of heroin from traditional source countries, and decreased capacity or willingness of major traffickers to continue large scale shipments to Australia.