Two Bangladeshi students are dead and a third is fighting for life after their car "disintegrated" in a high-speed crash in Sydney's southwest.

Police are investigating whether the three men were involved in a street race when their black Toyota smashed into a power pole on Canterbury Road in Belmore about 3.40am on Wednesday.

The 20-year-old driver and a 20-year-old passenger were killed.

A third man - believed to also be 20 - was in an "extremely critical" condition, according to police.

ABC News quoting police said that speed was a factor in the crash.

"We've examined a number of other vehicles from that scene and we're not ruling out a street-racing event.

"The background of the drivers is three Bangladesh students, probably all 20 years of age," the ABC News report quoted Traffic and Highway Patrol Command’s Superintendent Stuart Smith as saying.

The report said that the car smashed into an electric pole.

"The vehicle basically disintegrated when it hit the power pole," Superintendent Stuart Smith told reporters.

"We've examined a number of other vehicles from that scene and we're not ruling out a street-racing event."

Officers have spoken to the occupants of a white Nissan Skyline which was at the scene.

The Skyline's driver Ahshanul Fakhru denied the cars were racing and said the other driver, a friend, may have been having problems with his car.

"He lost control somehow and he was behind me and I heard him sliding on the road," Mr Fakhru told News Corp.

"Then suddenly, in a second, a big boom."

Police were still trying to locate the victims' families on Wednesday.

The Sydney Morning Herald reported that one man died on the spot.

Paramedics treated two others before taking them to the St George Hospital, it said.

QH