Large-scale seizures of heroin, cocaine and amphetamines by police do not reduce the number of overdoses or arrests for possession and use of the drugs, according to the largest Australian study ever conducted into the area.

The study by the NSW Bureau of Crime Statistics and Research (BOCSAR) also found that the frequency and quantity of heroin, cocaine and amphetamines being seized by authorities had no effect on theft, robbery and assault figures.

Big haul: A portion of the 585 kilograms of the drug known as "ice" seized in Sydney last year.

However, the authors warn against concluding that this means the pursuit of large scale drug busts is a waste of time and money as the risks associated with being caught continue to keep prices high and a lid on the amount consumed.