Sydney cyclist critical after hit by truck

A cyclist is in hospital with life-threatening injuries after being hit by a truck in Sydney's inner-west.

Emergency services were called to the intersection of May Street and the Princes Highway in St Peters at about 9am on Wednesday where a 26-year-old cyclist was trapped under a truck.

The man has been taken to Royal Prince Alfred Hospital in critical condition.

The 59-year-old truck driver was not injured but has been taken to hospital to undergo mandatory blood and urine testing.

Police are appealing for any witnesses to come forward.