Four-month-old baby missing in Melbourne

Police are searching for four-month-old baby who vanished from Melbourne.

Ralph Swinkels was last seen with his mother Brittany Lee in Seaford, a south-east suburb of Melbourne, about 6pm last night.

Police said they are concerned for the infant's welfare and have appealed to the public for any information on his whereabouts.

The duo were last seen in a grey 2009 Holden Captiva wagon. They are believed to be heading toward Ballarat.

Police have released an image of Ms Lee in the hopes it will jog a member of the public's memory.