The terrifying moment man lunges at Sydney cops with 20cm-long carving knife

A man has been arrested after allegedly attacking an officer outside a Sydney police station this morning.

CCTV footage captured the moment two constables were walking towards an Eastwood police station when a man lunged at one of them with a 20cm carving knife just before 3am, Nine reports.

The leading senior constable can be seen blocking the assailant's arm when the man swings at the officer's head twice before fleeing the scene on foot.

After a short pursuit, the still-armed man turns to face the officers when a third officer fires his Taser at the man, causing him to fall to the ground.

"This is one of these random, unprovoked incidents that unfortunately appears on the international stage far too often," an NSW Police spokesperson said.

"The officers are very lucky to not have been seriously injured or actually killed."