NSW man questioned after baby's death

A man believed to be the father of a two-month-old baby who died in southern NSW has been released from custody "pending further inquiries", police say.

The 32-year-old, named in media reports as Andrew Crichton, was arrested at Kooringal, near Wagga Wagga, after the infant was found "seriously unwell" early on Monday morning.

Paramedics treated the baby at the scene and he was rushed to Wagga Wagga Rural Referral Hospital but died.

Mr Crichton was released several hours later without charge pending further inquiries, a police spokesman said on Monday afternoon.

Detective Inspector Bob Noble said while the cause of the infant's death was unclear, the incident was being treated with "a degree of suspicion" and a post-mortem would be carried out.

The baby's mother was also questioned.