A full-scale search is underway in Port Phillip Bay for a missing crew member. Picture: NewsWire / Andrew Henshaw© News Corp Australia

A full-scale search is underway in Melbourne’s Port Phillip Bay after reports a crew member of a commercial ship is missing.

A Victoria Police spokeswoman said they responded to a commercial ship’s request for assistance about 8.30pm on Thursday.

A multiple-agency search is underway in the South Port Phillip Bay area involving Police Airwing, Australian Maritime Safety Authority Aircraft, HEMS Air Ambulance and water vessels.

The missing crew member, aged in his 30s, is believed to have gone missing after leaving port and approaching the heads.

Anyone with information is urged to contact triple-0 (000).

More to come.