POLICE hold grave concerns for a missing Bacchus Marsh woman who has a rare asthma-related illness.
Sarah Cafferkey, 22, vanished after going out with friends last Friday night.
Police said it is believed Ms Cafferkey visited a friend on Saturday afternoon in the Bacchus Marsh region but it is uncertain when she left her friend’s house.
Police and her family fear for her health, saying her medical condition requires regular Ventolin inhaler use.
Ms Cafferkey was last seen by family at home in Ross Street, Bacchus Marsh on Friday and has not made contact with her family since.
Her car, a 2001 silver Astra sedan registered OOHSEZ with black letters on a pink background, is also missing.
Police confirmed Ms Cafferkey has not used her bank accounts.
Ms Cafferkey is described as Caucasian with a fair complexion, 168 centimetres tall, thin build with black shoulder-length straight hair and green eyes.
It is not known what Ms Cafferkey was last seen wearing.
A community Facebook page, Help!! Have you seen Sarah Cafferkey?, was established on Tuesday had attracted more than 1200 likes by last night.
The page urges anyone with any information to call triple-0.
Friends have also posted pictures of Ms Cafferkey on micro-blogging site Twitter using the hashtag #findsarah.
New of her disappearance has reached Irish newspaper, The Journal, which claims her grandfather was from Achill Island in County Mayo, a four-hour drive from Dublin.
Ms Cafferkey’s disappearance follows cases of two Melbourne women who went missing in separate incidents last week but were each later found alive this week.