Pohiva Tu'ionetoa told FM Radio 87.5 it was a mistake, there would be no public consultation and the issue was dead.
Earlier former Education Minister and Tongatapu MP Penisimani Fifita told Parliament the growth of hemp plants was illegal, and so was the suggestion of a public consultation.
Mr Tu'i'onetoa revealed that an entity called "the Brown Group" had brought a proposal to Cabinet for the possible growth of hemp plants and public consultation around the issue.
The Prime Minister said Cabinet needed to be unanimous in their decision for a major issue such as the legalising of hemp.
He was not in Tonga during the Cabinet meeting alleged to have allowed for the public consultation.