How much cannabis is trafficked each year in Australia?

In 2013-14 there were 2,840 cannabis border detections in Australia. These detections amounted to a total weight of 158 kilograms (95% of which was seed). One large detection of 126 kilograms accounted for 80% of the total weight of cannabis detected during this period. 

Source: Australian Crime Commission (2015) Illicit Drug Data Report 2013-14.