A cyclist has died after a crash in Paddington on Tuesday morning.

In a bizarre and tragic set of circumstances, emergency services were already at the scene attending to an earlier crash nearby when the fatal incident occurred.

A man believed to be in his late 20s was rushed to hospital in a critical condition and later died after a collision with a vehicle.

Police and ambulance crews had been called to Moore Park Road near Lang Road about 6.50am to reports of a two-vehicle crash.

While treating the drivers of the vehicles for minor injuries, there was a second crash just metres from the first.

A police spokesman confirmed emergency services were still dealing with the first crash when they were called to the collision between a bicycle and a vehicle about 7.20am.

Paramedics performed CPR on the male cyclist, believed to have been in his late 20s. He was rushed to St Vincent's Hospital in a critical condition and later died.

A cyclist was killed in a crash in Paddington on Tuesday morning. Nick Moir

The driver of the vehicle did not require treatment, a NSW Ambulance spokesman said.

Cycling advocate John Sunde had been riding nearby when he found out about the crash.

“It just sounds like a horrible, horrible set of circumstances,” he said.

Mr Sunde, who knew the cyclist, said he was “a very delightful, pleasant young man” who trained and raced regularly in the area.

There were two crashes on the same stretch of Moore Park Road within half an hour of each other. Nick Moir

Moore Park Road was closed west-bound due to the crashes, with traffic backed up all the way to Bondi Junction and public transport delayed by 60 minutes at its peak.

Just after 11am, the road had been reopened and traffic was returning to normal.

Police have established a crime scene, and a report will be prepared for the coroner.

The cyclist's death is the second fatality on Sydney roads this week.

Large numbers of people were waiting at bus stops in Paddington on Tuesday morning due to an earlier crash. Mags King

Just after 8.30pm on Monday, emergency services were called to Slade Road in Bexley North after reports a man had been hit by a car.

Police and paramedics arrived to find a man unconscious on the road. Despite CPR, the man died at the scene.

The driver of the vehicle, a 19-year-old man, had stopped to help the pedestrian and spoke to police before being taken to St George Hospital for mandatory testing.