News weekly Der Spiegel has reported on its website that Admiral Giampaolo di Paola, who chairs the committee of NATO military chiefs, held a secret briefing for German MPs on Monday, in which he expressed the alliance's concerns, AFP reports.
There was grave concern that the cache of weapons may end up in other countries and with terrorists, the admiral warned, "anywhere from Kenya to Kunduz" in Afghanistan, Der Spiegel reports.
The missiles present "a serious threat to civil aviation", the Italian admiral reportedly said.
The report follows comments made by one of the officials in Libya's new leadership on the weekend in which he expressed concern about missing rockets, AFP reports.
General Mohammed Adia, in charge of armaments at the defense ministry, told reporters that "about 5000" SAM-7 anti-aircraft rockets were missing.
"Unfortunately, some of these missiles could have fallen into the wrong hands ... abroad," the general told reporters at a former arms depot of ousted Libyan strongman Muammar Gaddafi in Benghazi.
The United States has said it is working closely with Libya's new interim leaders to secure arms stockpiles, amid concerns over weapons proliferation.
The U.S. State Department has provided $US3 million to help destroy weapons, AFP reports.
According to a US State Department report, more than 40 civilian aircraft have been hit by such portable surface-to-air missiles since 1975, causing about 28 crashes and more than 800 deaths around the world, Sky News reports.