A major investigation is underway after a baby was found dead in a stormwater drain.

Police were called to the Perth suburb of Alexander Heights following the grisly discovery on La Salle Rd about 1pm on Monday.

WATCH THE VIDEO ABOVE: Baby found dead in stormwater drain in Perth’s north.

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“WA Police responded to reports that the body of an infant had been located in a stormwater drain,” authorities said.

“Multiple resources have been deployed to the location and an investigation into the circumstances surrounding this incident is currently underway.”

It is understood the baby was just days old and found wrapped in a sheet.

The discovery was made by tradesmen cleaning a stormwater drain, and police are yet to confirm who the parents of the child are.

A large police presence remains at the scene on Monday evening, with detectives speaking to nearby residents as they piece together what happened.

Anyone with information should contact Crime Stoppers.