A woman believed to be the mother of a baby found dead in a rubbish bin last month has been arrested, NSW Police say.

Authorities issued an appeal to find the mum after the tragic discovery of the newborn was made at a unit block on Harrow Rd at Auburn, Sydney, on the morning of August 31.

Now, more than two weeks later, police have provided a major update.

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“Following inquiries, a 24-year-old woman — who is believed to be the mother of the infant — was located and taken to hospital for assessment,” NSW Police said.

“Upon release from hospital, the woman was arrested and taken to Auburn Police Station where inquiries are continuing.” 

The newborn was unclothed and found inside a plastic garbage bag, police said last month.

It is believed the infant had been in the bin for up to 36 hours before being discovered.

“It’s very traumatic for that particular lady who found the baby, and of course the emergency services,” NSW Police Detective Assistant Superintendent Darren Sly said.

“It’s a newborn baby, who has now passed away, and of course, what else can we say? 

“It’s sad, it’s a horrific set of circumstances.”