The Arab League called Tuesday for an "urgent" Arab strategy to militarily back Libya's government against the Islamic State group, but stopped short of endorsing air strikes against the jihadists.

The Cairo-based Arab bloc issued its call after an extraordinary meeting to discuss a request by the internationally recognised Libyan government to adopt measures to confront IS which has seized the coastal city of Sirte.

"The Arab League affirms that given the difficult situation, there is an urgent need to quickly put an Arab strategy in place that includes assisting Libya militarily in confronting Daesh's terrorism," a League statement said, referring to IS by its Arabic acronym.

The internationally recognised Libyan government based in the country's east had on Sunday called for Arab air strikes against the jihadists.

"The Libyan air force is not capable of conducting air strikes against Daesh in Sirte," Libya's Foreign Minister Mohammed al-Dairi said in opening remarks to permanent delegates to the bloc on Tuesday.

"Libyan national security is Arab national security... Libya is suffering and we are fed up with the atrocities of the terrorist groups."

Libya, which plunged into chaos after the ouster and killing of dictator Moamer Kadhafi in 2011, has two rival governments and parliaments, as well as several militia groups battling to control its oil wealth.

IS, which already controls large swathes of territory in Iraq and Syria, has exploited this chaos, notably taking control in June of Sirte, 450 kilometres (280 miles) east of Tripoli.

In February, IS claimed the beheading of 21 Coptic Christians in Libya, mostly Egyptians, prompting air strikes by Cairo inside its western neighbour.

Since then, Egyptian President Abdel Fattah al-Sisi has pushed for a joint Arab military force to fight jihadists in the region.

Arab army chiefs have so far met twice in Cairo to work out the details of building the force after it was approved by Arab leaders at a summit in March.

A third meeting is due on August 27 in the Egyptian capital.