Two New Zealand navy ships Monday began a joint exercise with a Singapore navy vessel to strengthen interoperability between the two forces.

New Zealand Anzac class frigate HMNZS Te Kaha and replenishment tanker HMNZS Endeavour were taking part in the annual bilateral Exercise Lion Zeal off the east coast of New Zealand's North Island with Singapore frigate RSS Stalwart.

Exercise Lion Zeal, conducted since 2004, was intended to strengthen the close working relationship between the two navies and provided a chance for the two navies to practice their roles in maintaining regional security, said a statement from the New Zealand Defense Force.

"Lion Zeal gives us a valuable opportunity to work alongside the highly regarded Republic of Singapore's Navy," Te Kaha Commanding Officer, Commander Jon Beadsmoore, said in the statement.

"RSS Stalwart was commissioned in 2009 and is a very technologically advanced warship. I'm looking forward to testing ourselves against her and increasing interoperability between our two navies," he said.

"Our navy's Anzac frigates are a valuable contributor to regional security so it's important that we work seamlessly with other navies. It's also important that we are interoperable and combat capable so this will be the last major exercise we undertake before Te Kaha is upgraded with latest cutting-edge technology next year."

This year's Exercise Lion Zeal, from October 15 to 18, closely follows a three-day visit by Singapore Prime Minister Lee Hsien Loong earlier this month.

It was Lee's second visit to New Zealand since becoming prime minister in 2004.