Wellington Police are investigating an aggravated robbery at Khandallah Post Shop this afternoon.

Acting Detective Senior Sergeant Jason Perry of the Wellington CIB says Police were called shortly before 2:30pm this afternoon, after a male entered the Post Shop and presented a firearm at an employee.

"The offender demanded cash and was given an undisclosed amount before he left the Post Shop on foot."

Acting D/S/S Perry says Police are speaking to a number of witnesses this evening, including customers who were in the Post Shop at the time of the incident. A scene examination is currently underway.

"The offender is described as being in his mid-20's, olive-skinned of thin build and average height. He was wearing black jeans, white shoes, a black hooded sweatshirt with a red t-shirt underneath and a black beanie. It's possible he had a tattoo on his neck."

Anyone who witnessed any suspicious activity in the vicinity of the Khandallah Post Shop between 2pm and 3pm this afternoon or anyone who saw someone fitting this description in the Khandallah area today should phone Wellington Police on (04) 381 2000 or phone Crimestoppers on 0800 555 111.