The official death toll from the collision, which happened at the foot of the Blue Mountains during the morning rush hour, was put at five, with some 65 passengers injured.

But after visiting the site at Glenbrook, 55 km west of Sydney, New South Wales state premier Bob Carr told mediapersons up to a dozen people may have died.

``There are going to be, maybe, 10 or 12 families in New South Wales tonight who are going to be very sad,'' Carr said. ``It could be that high.''

Police said the front carriage of a Sydney-bound train packed with office goers and school children ploughed into the back of the cross-continent Indian-Pacific passenger train which was moving slowly on the same track.

Its first three carriages flew off the rails after the crash. The crash left the Indian-Pacific `embedded' in the commuter train.