A defence arrangement formed in 1971 between Australia, Britain, Malaysia, New Zealand and Singapore continues to remain relevant in dealing with today's security threats like terrorism, leaders from the five countries said yesterday.

Ministers from the Five Power Defence Arrangements (FPDA) members underlined this point at a meeting at the Four Seasons Hotel here.

Singapore's Defence Minister Ng Eng Hen said they "reaffirmed the importance of the FPDA as an integral part of the regional security architecture" and pledged their "unwavering commitment" to the pact.

The countries' militaries and defence officials have also been directed to update its relevance, in terms of exercises and integration of capabilities, to deal with the changing security environment.

The FPDA was conceived as a transitional pact to provide for the defence of Singapore and Malaysia.

In keeping with this remit, the leaders agreed to share intelligence to deal with terrorist threats against the two countries, they said in a joint statement. They will also further measures to strengthen counter-terrorism activities. "The FPDA has built trust and enhanced interoperability among the militaries of member nations, promoted respect for international law, and contributed to peace and security in the region."

Malaysian Defence Minister Hishammuddin Hussein said the FPDA "not only has the historical dimension, but also the trust between these five nations to face whatever challenges the world has got to face today". This includes winning hearts and minds to counter the narrative of groups like the Islamic State in Iraq and Syria which seek a foothold in the region.

Also at the meeting were Australian Defence Minister Marise Payne, New Zealand Defence Minister Mark Mitchell and British High Commissioner to Singapore Scott Wightman. British Defence Secretary Michael Fallon could not attend as he is standing in his country's general election next week.

The ministers also supported enhancing the FPDA's observer programme for non-members, in the spirit of promoting transparency.

Ms Payne noted that non-members have been invited previously to observe FPDA exercises. But there is scope to develop this further, such as involving the highest levels of other countries' militaries, she said.

Datuk Seri Hishammuddin said today's threats cannot be resolved by any one country, or among FPDA members. "The enemy we are facing is the same - they don't have silos, they don't work through geopolitical considerations," he said. "The way forward must be more inclusive," he added, hinting a more permanent representation of non- FPDA members may be possible.

Ms Payne said ministers discussed where they might "use the new capabilities that each of our nations is bringing online in the coming years". This, she added, "demonstrates the responsiveness of the FPDA, our ability to move with the times, notwithstanding our valuable age as a set of arrangements that have served us well."

Ministers also noted the scope and complexity of FPDA exercises had grown, and looked forward to marking its 50th anniversary in 2021.

Yesterday's was the 10th FPDA defence ministers' meeting, which is held every three years. Singapore and Malaysia take turns to host it.

The ministers also called on Prime Minister Lee Hsien Loong at the Istana, and on Malaysian Premier Najib Razak via a video conference.