Police are investigating links between separate incidents on Crown Street within two hours, with an identical suspect described in both robberies.

A convenience store was held up around 7.15pm by a hoodie-wearing man brandishing a long knife.

‘‘He used a 20-30 centimetre bladed knife, demanded cash, and made off with a small amount of money,’’ Detective Inspector Ben Hopper said.

Later, a restaurant on Crown Street was also the target of an attempted robbery. About 9pm, a man in a hoodie demanded money from staff, but escaped empty-handed.

‘‘It was exactly the same description as the other one. He demanded money, but no proceeds were obtained, and he ran away,’’ Det Insp Hopper said.

Victims of both incidents described a slim man between 25 and 30 years of age, around 175 centimetres tall, wearing a grey beanie with a white Adidas logo, a black hooded jumper and jacket, and dark jeans.

‘‘Police are making further inquiries, but we believe the two incidents are linked. We are exploring all evidence around those, but we are treating the two situations as linked with the same offender,’’ Det Insp Hopper said.

Anyone with information should call Crime Stoppers on 1800 333 000 or Wollongong police on 4226 7899.