A man has been arrested over a fatal e-bike crash which claimed the life of a pedestrian in Sydney's west.

A 65-year-old man was hit by the bike on Settlers Walk near Greenmeadows Crescent in Toongabbie about 9.50pm on Wednesday.

Emergency services rushed to assess the pedestrian while the rider allegedly fled the scene following the crash.

A number of police and paramedics were seen surrounding the path as the man was treated for injuries before he was taken to Westmead Hospital in a critical condition.

Police established a crime scene, which will be forensically examined by specialist by officers from the Crash Investigation Unit.

Officers were told the man died on Thursday.

Inquiries led police to arrest the rider in Seven Hills, a 45-year-old man, about 2.45pm on the same day as

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