A woman has been robbed of two handbags and her car keys in Hampton Park as part of a series of robberies in Melbourne’s south-east.

The woman was attempting to buy a phone for $1000 – organised through Facebook’s Marketplace – when the ambush occured, a Victoria Police spokeswoman has confirmed.

The victim had agreed to meet the online seller in a residential court in Hampton Park, where at least two locals witnessed the crime.

She had a baby and a toddler with her at the time of the incident.

Three men allegedly arrived at the court and grabbed the woman's and her sister’s handbags out of the car, running away through nearby wetlands.