TWEED police are investigating the use of a knife in the robbery of two bottles of bourbon from a South Tweed Heads supermarket.

Tweed Police alleged that two men entered the supermarket about 5.40pm Monday and went to the liquor section where they removed two bottles of bourbon from a display stand.

As one of the men was leaving the store he was challenged by a 28-year-old female employee who allegedly witnessed him removing the alcohol from the display shelf.

Police said the man produced a knife and threatened the employee before both men left the premises.

The first man has been described as Caucasian in appearance, about 45 years old, 178cm tall, medium build, short scruffy dark brown hair, unshaven and wearing a well worn black singlet and board shorts.

The man was bare footed and carrying a black nylon sports bag with a long shoulder strap.

The second man has been described as Caucasian in appearance, about 35 years old, 185cm tall, short light brown hair with an orange tinge and a freckled complexion. He was clean shaven and wearing a yellow T-shirt and white board shorts with black swirls and black thongs.

No person was injured during the incident.

Anyone with information about the robbery should contact Crime Stopper 1800 333 000.