Interpretations of the Mayan "Long Count" calendar point to an era of more than 5,000 years coming to a halt on December 21, although in Sydney it was business as usual.

With Australia one of the first countries to see the sun rise on what is supposed to be the end of days, Tourism Australia's Facebook page was bombarded with posts asking if anyone survived Down Under.

"Yes, we're alive," the organisation responded to fretting users.

Scientists in Taiwan also had their tongues firmly in cheek, setting up a two-story replica of a Mayan pyramid and planting an electronic countdown timer on top, drawing crowds at the National Museum of Natural Science.

Australian Prime Minister Julia Gillard set the satirical tone this month with a one-minute spoof address recorded for a youth radio station.

"My dear remaining fellow Australians, the end of the world is coming," she intoned.

"Whether the final blow comes from flesh-eating zombies, demonic hell-beasts or from the total triumph of K-Pop, if you know one thing about me it is this -- I will always fight for you to the very end."

In Asian capitals, many planned to party like there's no tomorrow with apocalypse-themed dinners and pub nights.

Hong Kong's Aqua restaurant promised to pick up the tab for its HK$2,112.12 ($273) six-course meal if the end is nigh -- though patrons will have to stump up if still alive at midnight.

Pubs from India to Malaysia have got into the doomsday spirit, with one in Kuala Lumpur hosting an "End of the World" party with global tunes until it all ends.

But although most saw the funny side, with an explosion of humourous banter on Twitter, elsewhere many worried that the ancient civilisation's calendar really will herald a fiery finish to human civilisation.

US space agency NASA has been contacted by thousands of worried people asking for advice on what to do. In a web page devoted to debunking the Mayan prophecies, it reassured them that the world will not end in 2012.

"Our planet has been getting along just fine for more than 4 billion years, and credible scientists worldwide know of no threat associated with 2012," it said.