Scene of a fatal crash on the Monaro Highway, where a Canberra man and a Queanbeyan woman were killed after their car left the road and rolled.

Scene of a fatal crash on the Monaro Highway, where a Canberra man and a Queanbeyan woman were killed after their car left the road and rolled. Photo: Elena Guarracino, Cooma-Monaro Express

A Canberra man and a Queanbeyan woman have been killed in a horror car crash on the Monaro Highway just east of Cooma.

A ute was travelling along the Monaro Highway near Rock Flat, about 10km east of Cooma, when it veered from the road about 12.10pm.

The Toyota Hilux rolled several times, before coming to rest on its roof.

The crash killed a 45-year-old man from the ACT and a 40-year-old woman from Queanbeyan.

The crash has blocked off the highway in both directions for a number of hours, with diversions in place at Nimmitabel and Cooma.

The highway has now reopened.

NSW Police inspector Neil Grey said there was no indication that any other vehicle was involved in the crash.

Inspector Grey said police were still attempting to determine why the ute left the road.

Police are continuing to investigate the circumstances surrounding the crash, and will prepare a report for the NSW Coroner.

It's the second fatal crash in the ACT region in as many days.

Two men were killed when their b-double truck veered off the Hume Highway, crashed through a road barrier, and fell down an embankment on Tuesday.

The crash occurred near Gunning, about 70km north of Canberra, just after midnight.

The 59-year-old driver, from Western Australia, and his 58-year-old passenger, from NSW, were killed.

The Monaro Highway near Cooma was the scene of another fatal crash just two months ago, when a b-double and a Honda SUV collided head on.

The crash killed a 74-year-old woman from Wanniassa, and left three of her family members, including a 14-year-old, in hospital.

In August, a tragic head-on crash on the Monaro Highway just north of Cooma claimed three lives.

A 15-month-old toddler was the only occupant to emerge from the crash unscathed, shielded from the impact by a baby capsule.