According to nzherald.co.nz, the player admitted to using cocaine but said it had been taken the night before the New Zealand Premiership Rugby League match between his team Waikato and Canterbury to help him cope with a very difficult personal situation. His mother was ill and had received a very complicated medical prognosis.

Drug Free Sport New Zealand reports that Riehana took the substance, cocaine, for his own non-competitive use and not to enhance his sporting performance. Cocaine does appear on the list of prohibited substances in the Sporting Code. However, it appears under a heading that reduces the penalty or sanction for the use of these specified substances if it can be justified that it was taken out of competition and, of course, not to enhance sporting performance. 

The Tribunal was lenient and decided to impose a three-month sanction, which will run until March 2024. Riehana will not be allowed to take part in any events, tournaments or competitions for the duration of his ban, which is governed by the rules of Drug Free Sport New Zealand. This includes the country's leagues in which he plays for Waikato.

Waikato, who play in the northern zone of the New Zealand league, were founded in 1921 and have been competing in the country's premiership since 1976. Waikato have won the competition three times, twice in 1992 and most recently in 2021.