A warning the increase in deaths and hospitalisations from stimulant overdoses - is likely just the beginning

New Drug Foundation data shows almost three New Zealanders die of a preventable overdose every week.

Executive Director Sarah Helm says while an increase in stimulant harm was expected due to a uptick in use, rates are still worringly high.

Helm says there's also been a growth in the number of fatalities from novel substances such as nitazenes , which are more potent than fentanyl.