A 22-year-old man died after a car and motorbike crashed in Arncliffe about 9pm on Sunday.

The motorbike rider died in hospital, and the male driver of the car was taken for mandatory testing but was uninjured.

In another fatal motorcycle crash on Sunday, a 25-year-old man crashed into a dividing barrier on Richmond Road in Marsden Park about 2.45pm. He died at the scene.

In an earlier crash on Richmond Road, Marsden Park, on Saturday, a 48-year-old rider struck a tree and died.

On Friday about 3.30pm, a 55-year-old motorcyclist died after he was thrown from his bike in the New England area.

The man was riding along Guyra Road near Tingha, when his bike failed to negotiate a turn and crashed into trees. He also died at the scene.

Reports on each death will be prepared for the coroner.

Assistant Commissioner Michael Corboy from Traffic and Highway Patrol Command, said motorcyclists needed to take more care on the roads.

"It needs to serve as a stark reminder of the dangers on our roads," he said.

"We have already seen 58 motorcyclists die on our roads this year. That is 58 people who have left to go on a ride, never to return home."

He said motorcyclists needed to take responsibility for their riding behaviour.

"I want motorcycle riders to remember that they are among the most vulnerable on our roads," he said.

"Motorcycles don't have airbags or seatbelts and, when they are involved in a crash, it is easy for a rider to be seriously injured or even killed."

There were five fatalities in total on NSW roads over the weekend, after a man died after a police chase in the Blue Mountains.

Police pursued the car after the 35-year-old driver failed to pull over for a random breath test at Lapstone on Saturday night.

The man's car collided with the median strip and then a tree, splitting the vehicle in two.

In South Australia, a motorcyclist died in a collision with a car south of Adelaide just before 6.45am on Monday.

The 21-year-old man died at the scene when his bike and a car collided on Kangarilla Road, police say.

The driver of the car was not injured.

With AAP