Three Royal New Zealand Navy staff have been stood down after the alleged use of illegal substances while on deployment overseas.
It is the second incident involving the alleged use of substances by Defence Force staff in three months, sparking concerns of a "systematic problem".
The Weekend Herald understands Australian Police searched the HMNZS Te Kaha with sniffer dogs on Tuesday while the ship was docked at Cairns.
It is understood the search took place after several staff failed drug tests related to class A substances.
A New Zealand Defence Force spokesman confirmed the navy was investigating the alleged use of illegal substances by three members while on deployment overseas.
"The three personnel have been stood down from their normal duties and have returned to New Zealand."
The spokesman wouldn't confirm any further details as the matter was under investigation.
A spokesman for Defence Minister Gerry Brownlee referred queries to the Defence Force.
Australian authorities contacted last night said they were not investigating the incident.
HMNZS Te Kaha has been in Australia for training in the lead-up to international maritime exercise, Rim of the Pacific, which is being held in and around the Hawaiian Islands and southern California from June 30 to August 4.
In March, five New Zealand Defence Force staff were stood down after an alleged incident involving an unknown substance while in Fiji to assist with the Tropical Cyclone Winston recovery.
It is understood the substance was a drug. The incident was investigated by the Defence Force.
Labour's Defence spokesman Phil Goff said two alleged substance-related incidents over a short period was "very concerning".
"Two separate incidents involving eight staff in a matter of months may indicate a systematic problem, rather than isolated incidents," he said.
"Operating equipment with impaired judgment endangers themselves and others.
"Using drugs is a serious offence. It's particularly serious when you're talking about uniformed personnel in work circumstances, whether working or training, that are representing New Zealand overseas."
Mr Goff believed drug use was a dismissable offence. He also believed the Defence Force should be looking very closely at how to deal with the substance use issue as a whole.
Meanwhile, Private Luke Brame was dismissed from the force in February after being found guilty of supplying fellow soldiers with the synthetic drug N-Bomb.