A police investigation is under way after a woman died in a crash on the Barton Highway near Yass on Friday.
NSW Police said on Saturday morning a man, aged 34, and a four-month-old baby were in a serious but stable condition at the Canberra Hospital.
The woman's age is not yet known.
Emergency services were called to an accident near the Yass Valley interchange at Manton about 3.50pm on Friday, where a car had left the road and hit a tree.
A female passenger travelling in the car died at the scene shortly after the crash, while the male driver and a baby were taken to hospital.
Officers from Hume Local Area Command and the crash investigation unit remained at the scene on Friday evening.
The Barton Highway was closed in the region for a number of hours, with a series of traffic diversions in place.
Anyone with information about the crash should call Crime Stoppers on 1800 333 000 or visit http://nsw.crimestoppers.com.au