Townsville police are investigating two separate armed robberies that occurred last night.

Around 10.40pm, police attended a video store in Idalia following a report that a man had presented a knife and stole cash from the till.  

The man was described a being Caucasian in appearance, approximately 170cm tall and tanned complexion.

Another robbery occurred at 12.40 where a man entered a convenience store on Thuringowa Road at Kirwan and selected a drink from the fridge. He produced a knife as he approached the counter and demanded cash from the store attendant.

The man stole money from the till and placed it in a backpack.  He was last seen running down Charles Street.

Police are searching for a man described as being Caucasian in appearance, aged between 40 and 50 years-old, 164cm tall, with dark hair included unshaven facial hair and wearing glasses. He was wearing dark green tracksuit pants, a grey and white coloured jumper and a brown hat.

No one was injured during either incident.

Police investigations are continuing.