Predominantly from the Salford area, officers are receiving reports that people on motorcycles or scooters are mounting pavements and snatching mobile phones from unsuspecting victims.
The offences are happening at the times people are commuting to and from work; between 6.30am and 8am and 4pm and 9pm.
Robberies with similar circumstances are also happening on the outskirts of Manchester City Centre near to Victoria Station and the Manchester Arena.
A CCTV image of an attempted robbery officers are treating as linked to the series has been released. It happened around 5.45pm on Wednesday 17 January 2018 on Blackfriars Road, Salford.
Police Constable Chris Jackson of GMP’s Salford Borough, said: “As the reports have come in, we’ve noticed a pattern and want to make people aware of what is happening while we try to put a stop to it.
“It’s so important that if people witness a robbery or become victim of a robbery that they contact us when they can, even if the offenders aren’t successful.
“I know the image is taken from a long distance but you can see the rider is wearing a white helmet and hi vis vest, which would stand out in the dark time the offences are happening.”
Anyone with information should contact police on 0161 856 6471 or the independent charity Crimestoppers, anonymously, on 0800 555 111.