Police have arrested and charged a 27-year-old man from Prospect overnight with two counts of aggravated robbery.

Just before 11pm, the man got on a Transit bus at the Paradise Interchange and when the bus was travelling off the O’Bahn onto Hackney Road, he allegedly threatened the driver and demanded cash.

The driver pulled over and the suspect ran off with a small amount of money.

He was not physically injured during the incident.

About ten minutes later, a man and woman were walking along Jerningham Street at North Adelaide when the same man allegedly told them he had a knife and demanded cash.

The couple handed over a small amount of money and the suspect fled.

Police set up cordons in the area and with the assistance of Dog Operations, the suspect was located on Brougham Place in North Adelaide.

He was taken to the City Watch House where he was refused police bail and will appear in the Adelaide Magistrate’s Court later today.

Police ask anyone who witnessed either incident to contact BankSA Crime Stoppers on 1800 333 000 or online at www.sa.crimestoppers.com.au