Egypt’s parliament has approved military intervention in strife-torn neighbouring Libya, citing the need to protect the national security of both countries, news broadcaster Al Jazeera reported.

According to the broadcaster, the legislature was unanimous in its nod to the deployment of armed forces on combat missions outside Egypt's borders to "defend Egyptian national security ... against criminal armed militias and foreign terrorist elements".

Egypt’s move comes after Libya's United Nations-recognised Government of National Accord (GNA) announced an offensive on July 18 to seize the coastal town of Sirte from rebel leader Khalifa Haftar's Libyan National Army (LNA).

According to monthly magazine The Africa Report, GNA military commanders said around 200 vehicles were on their way to Sirte from Misrata, increasing the likelihood of a confrontation between Libya’s various rival factions and their international backers.

Sirte is located northwest of Libya’s strategic oil crescent.

Egyptian President Abdel el Sisi warned in June that any attack on Sirte or the inland al-Jufra airbase would prompt Cairo to intervene militarily and protect its western border with Libya, Al Jazeera reported.

The Libyan government, which has the backing of Turkey in the conflict, denounced Egypt's threat of military intervention in its North African neighbour, labelling it a declaration of war.

Libya has been engulfed in conflict since the 2011 ousting of long time leader Muammar Gaddafi, which was backed by the North Atlantic Treaty Organization (NATO), an intergovernmental military alliance between North American and European countries.

The strife in the oil rich nation has pitted the GNA led by Fayez al-Sarraj and army commander Haftar’s self styled LNA.

In April last year, Haftar and his forces launched an offensive on Tripoli to seize control of the capital.