Illegal drugs worth millions of dollars - destined to fund terrorism - have been seized in a New Zealand navy-led counter-narcotics operation in the Indian Ocean.

French Marine Nationale frigate FS Languedoc this week intercepted and searched a dhow outside the Arabian Gulf suspected of smuggling, seizing more than 1525kg of hash and 166kg of methamphetamine, Royal New Zealand Navy captain Brendon Clark said.

The illegal cargo had a combined value of more than US$5.2 million ($7.4m).

Languedoc was patrolling in support of the New Zealand-led Combined Task Force (CTF) 150 when it seized the drugs, said Clark, the commander of CTF 150.

It's the task force's first major drug seizure while under Kiwi control.

"Languedoc has once again demonstrated that through collaboration with like-minded partners, CMF [Combined Maritime Forces] is able to seize and destroy millions of dollars' worth of narcotics, the income from which would otherwise be used to fund illicit activities and terrorism."

The outcome owed its success to the strong partnership between Combined Maritime Forces (CMF), the Marine Nationale and CTF 150, Clark said.

"CTF 150's mission is to disrupt criminal and terrorist organisations and their related illicit activities, including the movement of personnel, weapons, narcotics and charcoal.

"It supports the Combined Maritime Force, which is a multinational maritime partnership of 34 nations upholding international rules-based order. It counters illicit non-state actors on the high seas and promotes security, stability, and prosperity across approximately 8.3 million sq km of international waters, encompassing some of the world's most important shipping lanes."

The New Zealand-led multinational team took over command of CTF 150 from Canada this year.

It was great to have success this early in the New Zealand command, said Commodore Mat Williams, New Zealand Defence Force Maritime Component Commander.

"We're pleased to be able to make a contribution to global security, and it shows the value of working together with our partners in the CMF."