Police have released CCTV images of a man who may be able to help with their investigation into the attempted armed robbery of a convenience store in Lawnton on September 28.

At 7pm, a man armed with a knife entered the Ebert Parade store and approached two staff members, a 67-year-old man and a 66-year-old woman.

The man threatened the pair and made demands for cash.

The employees attempted to take the knife away from the man, and a short struggle has occurred.

The man left the scene on foot empty-handed.

The man is described as Caucasian with a thin build, 180cm tall, with short light brown hair and aged in his early to mid-20s.

The man is believed to frequent the Lawnton or Pine Rivers area in north Brisbane.