Tourism Australia's Facebook page was flooded early in the day with more than 1,000 posts asking, "Any survivors?" and "Are you guys still alive?"
Friday marked the end date of a 5,125-year cycle in the Mayan Mesoamerican Long Count calendar.
"Yes, we're alive," the government agency wrote to more than 117,000 "likes" and more than 12,000 comments before the agency took the post down.
The agency replaced it with 38 "Friday 'End of the World' Fan Photos," including a man swimming under crystal-clear water with a surfboard, a girl hugging a wombat, a koala peering out from a tree branch and a Queensland beach with a giant smiley face carved into the sand.
Some eschaton, or end-time, interpretations of the Mayan calendar suggest Dec. 21 marks the end of the world or a similar catastrophe because the calendar began 13 b'ak'tuns, or 5,125 years, ago, following three previous failed worlds, the last of which also lasted 13 b'ak'tuns.
That interpretation is "a disrespect to the Mayan culture and the indigenous people of Mayan descent," Ronaldo Camacho, a representative of a Guatemalan immigrant-rights group in New York, told The New York Times.
A New Age interpretation suggests the date begins a new era in which Earth and its inhabitants may undergo a positive physical or spiritual transformation.
A group called Unify was to have a global solstice "moment of peace" at 11:11 a.m. Greenwich Mean Time (6:11 a.m. EST) where "hundreds of thousands of people will be gathering at the major sacred sites of Jerusalem, the pyramids of Giza, Stonehenge, the pyramids of Mexico, the Taj Mahal" -- as well as in Los Angeles, San Francisco and other cities and towns -- for prayers and ceremonies from many spiritual traditions "unified for the harmony of the entire planet."
That was to be followed by an 8 p.m. GMT world meditation, Unify said in a statement.
"On Dec. 22, Unify hopes that we will enter the beginning of this new world age having participated, at least for a moment, in an experience of human unity," the organization said.
Modern Mayanist scholars say the ancient Mayans considered the end of the 13 b'ak'tuns to be a celebration.
"There will be another cycle," says E. Wyllys Andrews, former director of the Tulane University Middle American Research Institute. "We know the Maya thought there was one before this, and that implies they were comfortable with the idea of another one after this."