It's understood the toddler – who only turned two last month – was in her buggy at the time of the incident on Manor Street after 10am and suffered serious injuries when she was struck by the truck.
She along with her mother – who suffered minor injuries were rushed to University Hospital Waterford but the 2 year old was pronounced dead a short time later.
The road is currently closed to traffic and Garda forensic collision investigators are examining the scene. The coroner has been notified.
Gardai are also appealing for any witnesses to the incident to come forward.
In particular they're looking to speak to any passengers who were travelling on a bus on Manor Street at around 10 o'clock this morning and who saw the incident to come forward.
