Grandmother 'slashed by grandson' in NSW

A grandmother has been slashed with a knife after allegedly being attacked by her grandson in Sydney's west.

The 33-year-old man was visiting his grandma at Cambridge Park on Monday afternoon when an argument broke, police say.

The 71-year-old woman suffered lacerations to her arm as well as cuts and bruising from being physically assaulted and was treated at Nepean Hospital.

Her grandson fled the home before police arrived and investigations into the assault continue.