NATO on Monday examined proposals to turn the Western military shield of the Cold War era into a new international security presence for the 21st century.

The North Atlantic Treaty Organisation must continue to assure security for its member states -- now stretching from the United States to Turkey -- as it has done since 1949 but must also be increasingly prepared to intervene far beyond its borders, according to a long-awaited report by an experts group led by former US secretary of state Madeleine Albright.

"In the coming decade, NATO will have four central inter-related military missions," the experts' group said in its 'New Strategic Concept' for NATO published Monday, the first such strategic look at NATO's role since 1999.

The first requirement is to "deter, prevent and defend" against aggression so as to ensure the political independence and territorial integrity of NATO member states, conforming to the alliance's original 60-year-old mission.

"The report confirms that NATO's foundation are as important as ever... the commitment to collective defence," said Albright, presenting the report by her 12-strong group.

But the report also insists on the need to send out military missions beyond the treaty area "when required to prevent an attack on the treaty area or to protect the legal rights and other vital interests of Alliance members" -- the sort of expedition already seen in Afghanistan, a mission provoked by the extraordinary September 11 attacks in the United States in 2001.

"NATO allies must face our challenge abroad," and the "dynamic engagement" required "means we have to deepen partnerships" outside of NATO's borders, said Albright.

Accepting the report, NATO Secretary General Anders Fogh Rasmussen assured that "NATO has no ambition to become the world's policeman," stressing that any expeditionary mission must be based on the principles of the UN charter.

The text was also submitted to ambassadors of the NATO nations for consideration.

The new concept will then be examined and amended before being submitted for adoption by allied leaders at a November summit in Lisbon.

Despite the assurance, this "expeditionary" aspect of the report's thinking risks raising hackles in Moscow as well as in Beijing and other emerging powers.

Another key plank of the experts' proposals is to cooperate better with those partners, and others worldwide, in order to tackle the new threats posed by cyberattacks, piracy, arms proliferation and energy supply insecurity and climate change.

The reports' authors also stress that NATO, born into the post-WWII Cold War era of mutually assured nuclear destruction, must now "have a fuller role in dealing with the emerging ballistic missile threat" from the Gulf, which will be a theme of the Lisbon summit.

Another global goal is to "help to shape a more stable and peaceful international security environment" by providing military and police training, coordinating military assistance, in less stable countries, as NATO is already doing in Afghanistan and Iraq.

However, in order to achieve the new goals, NATO "must halt the precipitous decline in national defence spending," and to introduce reforms to make spending more efficient, the report says.

One of the 12 experts -- Bruno Racine, head of France's Strategic Research Foundation -- said he expected "difficult" debate between the allies on reform of the alliance and its military structures.