The man allegedly entered a Burelli Street liquor store armed with a knife just after 1.30pm on Saturday.

He threatened a shop assistant with the blade and demanded cash, according to police.

The assistant handed over the cash, and the man was last seen running west along Burelli Street.

Officers from Wollongong Local Area Command attended and established a crime scene.

The 23-year-old attended Wollongong Police Station about 3.15pm on Saturday and was placed under arrest.

He was charged with armed robbery and was refused bail to appear at Wollongong Local Court on Sunday.