Mea culpa, mea culpa, mea maxima culpa! I didn't record the various sources that I found when I was researching the question, so I can't post them here. Needless to say that I did find the references in order to satisfy my curiosity. The following is an extract from this Wikipedia entry summarises what I found. https://en.wikipedia.org/wiki/Hunter_Valley_cannabis_infestation
Cannabis sativa seeds first arrived in Australia in 1788 on the First Fleet at the request of Sir Joseph Banks. The blueprint for the New South Wales colony, approved by the British Cabinet in 1786, envisaged Australia as a commercial colony producing hemp.
The blueprint for the New South Wales colony was created for the British parliament in 1786. Banks provided a supply of seed. However, the British were too optomistic about the rate of establishment ot teh colony which would have failed due to starvation had Governor Phillip not done all he could to keep everyone alive, but on meagre rations until replenishment occured. Settle yourself down and watch this video which will enlighten you as to the first ten years of the colony. The video is an Australian prodcution aand one of a series dealing with early British colonisation of Australia.