Masked robbers hold up Sydney chemist

A pair of armed robbers have assaulted a staff member when holding up a chemist shop on Sydney's lower North Shore.

Police say two masked men, dressed all in black and carrying a machete and screw driver, entered the chemist on High Street, Willoughby, at around 8.30pm on Wednesday.

They escaped with prescription drugs and cash and were seen jumping a fence on Summerville Crescent before running through a car park on Crabbes Avenue.

An investigation is underway with police appealing to the public for any information.