An elderly man has died after he was hit by a train at Edithvale Station in Melbourne's south-east on Tuesday afternoon.

Police said the man was crossing the tracks on a bicycle from Nepean Highway to Station Street around 3.30pm when he was hit by the Frankston-bound train. 

The man, who is yet to be identified, died at the scene.

He was the second person to be killed on the Frankston line in four days - 17-year-old Jack Irving was killed on Friday night.

The circumstances surrounding the latest death are unclear and police are investigating.

Metro said the Frankston line reopened between Mordialloc and Carrum at 6.30pm. Buses had replaced trains for that section during the afternoon after the incident.

Metro warned passengers to expect 10 minute delays while they recover their services.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppersvic.com.au.