The first incident happened at about 11.15pm on Friday, June 7, when a taxi waiting for a pre-arranged fare in Longfellow Drive was approached by two men who threatened him with a knife before stealing cash from him.
The suspects are described as two white men.
The first was aged around 25, 5ft 5in, of medium build with dark hair, wearing dark clothing and carrying a knife.
The second was aged around 23, 5ft 4in, of medium build and with dark hair, wearing a white shirt.
The second robbery happened at about 3.40am yesterday (Sunday, June 9), when a driver arrived in Wingate Close to collect a booked fare.
As he turned his vehicle around, two men approached and opened the car’s front doors, before the driver was threatened with a large knife and a wallet containing cash stolen.
The first suspect is described as white, under 5ft 10in, of average build.
He was dressed in dark clothing, including a top with the hood pulled up, and a scarf over his face.
The second man is described as black, slightly taller than the first man and of a slightly bigger build.
He was also dressed in dark clothing and had his face covered.
Anyone with information about either incident is asked to call Northamptonshire Police on 101. Information can also be shared with Crimestoppers anonymously on 0800 555111.