At issue was the interpretation of section 92 of the Australian Constitution, a provision which relevantly states:... trade, commerce, and intercourse among the States, whether by means of internal carriage or ocean navigation, shall be absolutely free.The court decided that s.92 prohibits burdens upon interstate trade, commerce, and intercourse of a 'protectionist kind'.

[2] This was partially the consequence of inconsistent and confusing jurisprudence under the previous interpretive approach, as was acknowledged by the joint judgement.

The Fisheries Act 1959,[5] empowered the Governor of Tasmania to make regulations relating to a number of subjects, one of which was the classification of undersized fish.

[6] Whitfield and his company imported some crayfishes from South Australia for reselling, which were undersized under Tasmanian regulations.

[1]: at paras 3–4 The Court decided that s.92's effect on interstate trade and commerce, was only to make it immune from 'discriminatory burdens of a protectionist kind'.