The abandonment of a baby boy in a western Sydney drain has sparked renewed calls for emergency hatches to be rolled out nationally.

A group of cyclists riding on a bike track beside the M7 highway at Quakers Hill heard his cries from the 2.5 metre drain around 7.30am on Sunday.

Police who rescued the baby said there were no signs of physical injury, but said he was malnourished.

Believed to be just two or three days old, the baby remains in a serious but stable condition at Westmead Children's Hospital.

Germany and Canada are among countries that have baby hatches, mostly attached to hospitals, where parents can safely place unwanted babies, and trigger an alarm to alert staff.

Labor Senator Helen Polley believes the idea has merit and has called for a national response.

Baby abandonment is currently treated as a criminal offence, with parents liable for prosecution.

Senator Polley wants baby safe havens established across the country in places such as fire stations, police stations and hospitals.

"Here, a parent could legally abandon a baby without fear of criminal prosecution," she said.

"Let's make sure mothers and babies are provided (with)... the compassion of a modern society."

OTHER ABANDONED BABIES

* 2013 baby left outside ambulance station in Rockhampton, Qld

* 2013 baby, nicknamed Moses, left outside a family's home in Logan, Qld

* 2011 baby Willow found dead in a Kingston park, Tasmania.

* 2007 baby Catherine left outside Dandenong hospital, Victoria

* 2007 baby Joan left on the doorstep of a Sydney church