A 28-year-old man will face a Hobart court later today, charged with the armed robbery of a newsagency in the state's south yesterday.
Police allege that the man entered the Lenah Valley Newsagency and Post Office about 4.30pm yesterday wearing a balaclava, and brandished a knife at a staff member and demanded money.
It is alleged that the man stole cash from the register and ran off.
Police say that a staff member stood between the alleged offender and a female staff member.
"A struggle occurred but the staff member was not injured," Acting Inspector Craig Joel said.
Drug squad detectives and traffic police were patrolling in the area at the time and located a vehicle of interest at New Town.
Acting Inspector Joel said a subsequent search was conducted in the area and four people were arrested by police and a sum of cash was also seized.
A second man and two women are assisting police with their inquiries.
Police would like to hear from anyone who saw a maroon-coloured Holden Commodore sedan parked near the newsagency at the time of the alleged robbery.
Anyone with information is asked to contact Crime Stoppers on 1800 333 000.