A disturbing and controversial image has emerged of a baby sitting in the middle of train tracks while its mother is taking photos.

The baby is seen hunched over as its mother and another unidentified person take photos while on the tracks.

A few metres away a third person is seen standing beside a pram, assumed to belong to the baby.

The image of the incident, which was captured in Fremantle, Western Australia, was posted to The Bell Tower Times Twitter account.

"Now trending on Instagram: babies on train tracks. Spotted in Freo (Steve C)," the caption, which accompanied the photo, read.

According to the Public Transport Authority, staging photographs on train tracks in Australia is illegal and seen as trespassing.

The West Australian reported a warning sign had been placed at level crossings to warn of the dangers as it was "dangerous and illegal".

"Being on the tracks or within the rail reserve, without a permit and other than for traversing a pedestrian crossing, is classified as trespassing," PTA communications manager David Hynes said.

While some people defended the mother by saying the tracks were no longer in use, others shut the theory down, saying freight trains still use the rail line in question.

"For those that are saying no trains you better do some research because freight trains still use it carrying shipping containers from the port," one person said.

Others took aim at the mother saying she's not fit to be a parent.

"It's a shame the cops didn't see it and do them for child endangerment."