Toe severed in Sydney CBD bike crash

A woman is fighting to save her big toe after it was severed in a crash in the heart of Sydney's CBD.

The 43-year-old was riding pillion on a motorcycle in Haymarket around 10pm on Thursday when it ran into the back of a taxi which had stopped suddenly on the corner of Pitt Street and George Street, witnesses told police.

In the crash, both the 34-year-old female rider and her passenger were thrown heavily to the ground, resulting in the latter's left big toe being cut off.

She was taken to Royal Prince Alfred Hospital where she is waiting to hear whether the toe can be surgically reattached.

The motorcycle rider was taken to hospital with non-threatening injuries, and will undergo a mandatory blood test.

The male taxi driver was unhurt and passed a breath test at the scene.