Man, 20, dies after Sydney car smash

A 20-year-old man has died in hospital from critical injuries after his friend's car rolled and landed on a safety barrier near Sydney airport.

The man had to be freed from the front passenger seat of the Mitsubishi Lancer after the crash in the southbound lanes of General Holmes Drive, at the start of the airport tunnel, at Mascot about 9pm on Tuesday, police said.

He died in St George Hospital on Wednesday morning.

The 18-year-old man who was driving and three other passengers, two 18-year-old women and a 20-year-old man were taken to hospital for checks.

Witnesses to the crash are urged to contact police.