New Zealand has signed a pact with Australia to deepen cooperation between both countries' navies.

The pact - named Plan Tasman - will strengthen cooperation across personnel, training, development, warfighting, engineering, regulation and international engagement, statements from both countries said.

Plan Tasman was signed by Royal Australian Navy Deputy Chief Rear Admiral Darren Grogan and Royal New Zealand Navy Deputy Chief Commodore Karl Woodhead.

"Plan Tasman builds on generations of cooperation between our navies and provides a practical framework to strengthen the way we train, operate and develop capability together," Grogan said.

Woodhead said the two countries' maritime relationship was established more than 160 years ago and has been strengthened over generations in war and peacetime.

"Our strategic guidance is to deepen and formalise the alliance," Woodhead said, describing the plan as "a shift from a history of cooperation based on tradition to integration by design".