A man has allegedly threatened a supermarket worker with a knife and fled with stolen tins of baby formula in north-west Sydney.

A man entered the supermarket on Rowe Street, Eastwood, with another man on Tuesday afternoon.

One of them removed several tins from the baby formula aisle, stashed them in his backpack and tried to leave the store.

An employee saw the incident and asked to see inside the man’s bag once outside the store.

When the 37-year-old employee found the formula the man tried to grab the bag and run.

He then allegedly threatened the employee with a knife and ran off with three tins of formula.

The armed man has been described as being Indian/ Sub-Continental in appearance, aged in his 40s, about 175cm tall with a slim build, short dark hair and wearing a grey jumper, jeans, black Nike shoes with white soles and a black backpack.

Image: Getty