He would not comment on whether putting ground troops in places such as Syria would help move towards the aim of creating some kind of order.

"I would leave that to other people to make decisions rather than me proffering advice from the sidelines. There's no military answer to this. The military response will be part of the overall response but this is going to take an enormous international effort to try and bring some degree of some governance and stability to some of the countries inside the Middle East," he said.

"And anyone who thinks this is going to be solved quickly by dropping bombs is going to be very disappointed. It's going to take much more than that."

Morrison, who retired this year after 36 years in the army, was as shocked as anyone by last week's bloodbath in Paris at the hands of suspected Islamic State extremists.

"Like everyone, I'm heartsick that such brutal violence would be wrought on men and women of all ethnic backgrounds. I mean, there were men and women of Islamic backgrounds killed in those attacks in Paris," he said.

"This is not a religious movement. They are brutal.....Oh, words fail me."

Morrison said he was often asked for an answer on how to solve the horror of terrorism.

"I think I'm probably old enough and maybe wise enough to know that I don't have any of the answers but then so few people do," he said.

"I suspect it's going to take a very long time for this to work itself out because parts of the issue is what's happening within the Islamic faith, what's happening in the national entities which make up the Middle East, what's happened in Iraq and Syria and other countries.

"We do have to respond as a global community."