About 7.15pm, a 46-year-old man and a 44-year-old woman were working at a takeaway store on The Entrance Road, Long Jetty, when an unknown man entered the store armed with a handgun.
The man threatened the pair and demanded cash, before the 46-year-old grabbed a mop nearby and began to chase the offender.
The man ran from the store and was last seen running east along Stella Street.
He is described as being of Caucasian appearance, aged in his 30s, between 170-180cm tall, with a thin build, wearing shorts and a dark coloured hooded jumper.
Anyone who may have CCTV or dashcam footage from nearby either location between 6.30pm and 8pm or who may have seen or heard anything suspicious is urged to contact Wyong Police on 4356 6099 or to call Crime Stoppers on 1800 333 000.