A truck driver who allegedly hit and killed a grandmother on the northern beaches last week fled the scene and threw her clothing in a bin after peeling it off the bottom of his vehicle, police say.

Jo-Ann Thwaites, 60, was hit on Friday morning while using a zebra crossing at the intersection of Old Pittwater Road and Condamine Street in Brookvale after doing some grocery shopping with her son.

Lilydale Chickens driver Emmanuel Xiberras, who was doing deliveries in the area for the poultry company, allegedly drove off after knocking Mrs Thwaites down.

A second truck, pictured at the scene with Daikin branding, then hit Mrs Thwaites and dragged her up to 600 metres before the driver realised and stopped to help. He has not been charged.