"This guy on a push bike came out of nowhere and bowled Jaxxyn completely over ... He went straight down, face down".
After knocking the toddler over, the cyclist unleashed a torrent of abuse before riding off, up John Wilson Ocean Dr, she said.
"He swore at Jaxxyn, called him a little bastard ... I told him he shouldn't be on the footpath riding a bike anyway."
Scott took her shocked nephew to a GP, where the extent of his injuries became clear.
"They called the ambulance because he looked ... dazed, pale white."
X-rays revealed Jaxxyn's left leg was broken in two places, and he had also suffered head and abdominal injuries.
He spent the night in hospital before being discharged yesterday.
Doctors said his recovery would take six to eight weeks.
Scott had a blunt message for the cyclist.
"Come forward - it's unfair putting a 3-year-old through so much pain."
Acting Sergeant Steven Wykes, of Dunedin, yesterday appealed for sightings of the man, described as between 30 and 40 years old, 170cm-175cm tall, with grey/white hair and a beard of the same colours, wearing an orange/yellow top, orange/brown shorts, white shoes and riding a red/orange mountain bike.
Dunedin police (03) 471-4800, Crimestoppers 0800 555-111.