UPDATED 5:44pm: The Defence Force has discharged five soldiers, for using drugs.

The group used the psychoactive substance NBOME over Labour Weekend.

Spokesman Major General Peter Kelly said their behaviour was unacceptable and he'll do everything he can to ensure the New Zealand Army is drug-free.

"The debilitating impact on the trust and the erosion of trust which is absolutely crucial to the functioning of an army - there's just no place for it."

He said discharging the group sends a strong message to other soldiers that drugs have no place in the Army.

Three other soldiers who were also involved in the incident will be court-martialed.