17/12/2016 9:13 AM AEDT | Updated 18/12/2016 7:48 PM AEDT

Eight Dead In Horror 48 Hours on Nation's Roads

The Christmas road toll continues to climb.

Three lives have been lost in a deadly 24 hours on the nation's roads.

It's been a shocking weekend on the nation's roads, with eight people including a cyclist killed as the horror start to the Christmas period continues.

A 33-year old woman was travelling with a small group of cyclists travelling southbound on Mona Vale Road, Sydney, when she collided with a Toyota Corolla on Sunday morning. She was seriously injured and died at the scene.

The 37-year-old male driver will undergo mandatory drug and alcohol testing, police said. Investigations into the circumstances surrounding the crash are ongoing.

On Saturday night, a baby girl died after a two-car collision on Phillip Island, south of Melbourne. The infant was rushed to hospital but couldn't be saved, police said.

Four other people were injured in the smash that occurred around 7:30pm on Saturday. The 24-year-old driver of one of the vehicles is said to be under police guard in hospital.

Also on Saturday night, three people lost their lives after the car they were travelling in crashed into trees in Queensland.

Police said the horror crash, near Bundaberg, occurred when the vehicle lost control at the intersection of Birthamba Road and Bishop Drive in Bucca about 7pm.

The awful period on the nation's roads started late Friday when a man died on the Mornington Peninsula after the car he was driving hit a power pole just before midnight.

Police believe the car was travelling east on Boundary Road in Dromana when his car left the road, leading to the fatal smash.

In NSW, police are preparing a report for the Coroner after the death of a man in a single vehicle crash in the state's west on Saturday morning.

That fatal crash occurred shortly after midnight at the Great Western Highway, 10km west of Bathurst. The vehicle is believed to have veered off the road and rolled.

The male driver aged in his 20s died at the scene.

Meanwhile, a young man was killed on the South Australian roads just before 2am on Saturday.

Police and emergency services were called to Kubenk Road, at Rockleigh, after a station wagon rolled. The driver, a 23-year-old man from Tungkillo, died at the scene.

His passenger, a 23-year-old man from Birdwood, was taken to the Royal Adelaide Hospital with minor injuries, police said.