An 11-month-old baby girl from Mandurama in New South Wales, Australia, has died after falling off a trampoline. Police authorities, however, eye her death as suspicious.

The baby girl was taken on Wednesday to the Blayney Hospital around 11 am by a 35-year-old man who claimed to be her stepfather. Her mother wasn't around at the time of the accident.

Blayney Hospital doctors immediately performed CPR, but they were unable to revive her. She died a short time later.

Officers were told the baby had fallen off a trampoline at the family's home.

Police, however, eye her death suspiciously. Forensic officers have joined into the investigation. Homicide squad detectives have also been called in.

"We are treating the death at this stage as suspicious and are looking into that circumstances," Inspector Colin Cracknell from Bathurst Police said.

"We have got police from the homicide squad and the state crime command coming up to assist us today."

Luke Rankin, Chifley Local Area Command detective inspector, said the family's movements are currently being watched.

"I'd really like to appeal for anyone in the community that may have information about the family or their movements during that time," Blayney Chronicle quoted him as saying at the Bathurst police station on Thursday morning.

Anyone who has information about the incident are being encouraged to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page at www.police.nsw.gov.au.