A manhunt is underway for an e-scooter rider who assaulted two men in the CBD last night.

The victims — men aged 34 and 49 — were involved in an altercation with the unknown man, who was travelling on an e-scooter on Collins Street at about 10.30pm.

Both victims suffered head injuries and required hospitalisation.

The pair have since been discharged from hospital.

Anyone who witnessed the assault is urged to contact Crime Stoppers on on 1800 333 000 or submit a confidential report at crimestoppersvic.com.au