Emergency services were called to an accident near the Yass Valley interchange at Manton about 3.50pm, 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.

NSW Police said the conditions of the two injured people are not yet known.

The woman's age is not yet known.

Officers from Hume Local Area Command and the crash investigation unit remained at the scene on Friday evening.

At 6.20pm, police said the Barton Highway was expected to remain closed in the region for a number of hours, with a series of traffic diversions in place.

All northbound lanes of the Barton Highway are closed in Manton due to a car crash near Yass Valley Way.

Light vehicles are being diverted at Murrumbateman via Murrumbateman Road, Sutton Road, Gundaroo Road and the Hume Highway.

Vehicles over 19 metres travelling between Canberra and Yass should use the Federal Highway and the Hume Highway via Gunning.

Motorists are advised to allow plenty of extra travel time.

Emergency services and traffic crews are at the crash site.

Anyone with information about the crash should call Crime Stoppers on 1800 333 000 or visit http://nsw.crimestoppers.com.au.