"It seems likely that it may have originated in the Australian context," dictionary editor Katherine Martin told AAP.
"The earliest evidence that we know of at the moment is Australian and it fits in with a tendency in Australian English to make cute, slangy words with that 'ie' ending."
There's barbie for barbecue, firie for firefighter and tinnie for a can of beer.
Oxford Dictionaries says in mid-September 2002, an Australian wrote on ABC online: "Um, drunk at a mates 21st, I tripped ofer [sic] and landed lip first (with front teeth coming a very close second) on a set of steps. I had a hole about 1cm long right through my bottom lip. And sorry about the focus, it was a selfie."
Although "selfie" can be traced back more than 10 years, it only gained momentum throughout the English-speaking world in 2013.
Research suggests its frequency of use has increased 17,000 per cent over the past 12 months.
Popstar Rihannah is a serial selfie taker:
The word was often spelled "selfy" early on but "selfie" has become the accepted spelling.
"The use of the diminutive -ie suffix is notable as it helps to turn an essentially narcissistic enterprise into something rather more endearing," editorial director Judy Pearsall said in a statement.
By 2012, "selfie" was being used commonly in mainstream media while former Prime Minister Kevin Rudd helped popularise the term in Australia.
Selfie was added to the common-usage Oxford Dictionaries Online in August this year, with the definition: "photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website."
The Oxford Dictionaries Word of the Year 2013 is 'selfie': http://t.co/ifwIYh4o6e #WOTYselfie
The term is also being considered for inclusion in the definitive Oxford English Dictionary.
"There's a very good case (for inclusion) ... if it continues to be as common a word as it is now," Ms Martin said.
"We now know that it has a long history."
Selfie was selected as the 2013 word of the year from a shortlist that included binge-watch (to watch multiple episodes of a television program in rapid succession), showrooming (the practice of visiting a shop in order to examine a product before buying it online) and twerk (to dance to popular music in a sexually provocative manner).
- AAP