Wellington Police investigating an aggravated robbery at an inner city restaurant on Sunday night believe a stolen cash register may lead them to the offenders.

Two men, one armed with a gun, the other with a knife entered Daawat Indian Restaurant around 9:20pm on Sunday night, demanding cash from staff.

Detective Sergeant Shane Dye of the Wellington City CIB says the pair entered the restaurant via an alleyway on Dixon Street with their faces concealed and held a gun to the head of an employee, before making off with a cash register.

"The pair then fled in a dark-coloured Toyota ute, leaving staff shaken but unharmed."

They were described as either European or Maori, about 6 feet tall, wearing dark-coloured clothing and may possibly be in the wider Lower Hutt area.

Detective Sergeant Dye is appealing to any mothers, partners, family members or friends who saw these offenders come home with a cash register late on Sunday night, with a small amount of cash.

"This aggravated robbery left the victims extremely shaken and we want to find these offenders as soon as possible. Anyone with any information should phone us on (04) 381 2000 or phone Crimestoppers on 0800 555 111."