Hill, who was speaking at a question-and-answer session at the Asia Security Conference here, said the FPDA should only be expanded provided it did not erode the existing usefulness of the annual defence exercises held jointly by all five members.

The five members -- Australia, New Zealand, Singapore, Malaysia and Britain -- must also agree on the move if it does materialise, Hill said.

"Can it be taken one step further to be a useful organisation in relation to cooperative endeavors to beat the threat of terrorism?" Hill said.

"And if you ask me personally, I think it can but it will only work if the five states actually agree that to be so."

Earlier in his speech, Hill said FPDA members were currently involved in a debate relating to "the value in extending Five Power Defence Arrangement exercises, from those addressing conventional threat, to include terrorist threats".

WAR.WIRE