A MAN wearing a sombrero robbed a bank at gunpoint in Brisbane's south.

The man allegedly walked into the Carina branch of the Bank of Queensland on Old Cleveland Road about 3.30pm on Tuesday and demanded cash from a female employee with a gun.

The man then ran from the bank with a bag the 41-year-old employee had filled with cash.

The man was described as being Caucasian and about 184cm tall with a slim build.

His face was covered, but he was also described as being in his 50s with a grey, stubby beard.

The man was last seen wearing an orange shirt, blue jeans, the hat and a pair of sunglasses.

Police investigations are continuing.