The 10-year-old victim was described by Lennox Head All-Girls Surfriders Club spokeswoman Georgia Laddin as a local girl and a regular surfer at the beach on Australia's east coast, 200 kilometers (124 miles) south of Brisbane.
The girl was taken to Lismore Base Hospital by paramedics who described her wound as "a significant hand injury, " Her hand and wrist were bitten.
Lifesaving duty officer Jimmy Keogh told the Sydney Daily Telegraph there were no sightings of sharks at the time of the incident, and said an investigation is continuing.
Laddin said she believes it was not a shark attack
"It was a mackerel. She's been bitten by a fish. She's fine, she's OK," Laddin said.
A police spokeswoman said it was too early to confirm it was a shark that bit the swimmer, the Brisbane Times reported.