Sydney man stabbed dead after fight

One man is dead and another is under police guard in hospital after a stabbing in Sydney's east.

The pair, one aged in his 50s and the other believed in his 30s, were involved in an altercation at a fast food outlet, police say.

Officers were called to Oxford Street at Bondi Junction following reports a man had been repeatedly stabbed just after 8pm on Saturday.

Paramedics and police performed CPR but the older man died at the scene.

The younger man was also injured. He was arrested and taken to St Vincent's Hospital under guard with his condition not known.