Man arrested after baby's death in NSW

A man has been arrested after a seven-month-old boy died in suspicious circumstances in NSW's Hunter region.

Police say the 36-year-old was taken into custody after a vehicle stop on the New England Highway at Muswellbrook just after 6.30pm on Wednesday.

He was taken to Muswellbrook Police Station but no charges have been laid.

The man's arrest comes after a seven-month-old boy was taken to Muswellbrook Hospital in an unresponsive state on Sunday afternoon and couldn't be saved.

The hospital contacted police, who set up a crime scene at an Aberdeen home.

Officers have been in contact with the child's mother and her immediate family, who are from the local area.

They have also been speaking to people who had contact with the baby in the days and hours leading up to his death.