End Of The World groups who believe a French village will be their saviour have been told they are not welcome.
Followers believe a nearby mountain has magic powers and are convinced UFOs will rescue them and take them to safety.
French authorities have insisted the scenario is ridiculous, but they are taking the situation seriously.
"My message is very simple. I am telling people don't come here to Bugarach for a simple reason there will be nothing to see here. So I insist don't come here, especially as there will mainly be the police here," he said.
In the nearby ancient town of Carcassone, officials say they are planning for every eventuality.
"Taking into account the huge media interest this affair has created we have to take into account all security concerns and be prepared for all outcomes whether there are 300 people or 3,000," said security chief Eric Freysselinard.
Villagers appear not to be too concerned about claims of impending doom.
Many said they were doubtful that extra-terrestrials would be coming to pluck survivors to safety.
"I think it's a big load of nonsense. I don't think there are UFOs within the Bugarach mountain," said local rubbish collector Jean-Luc Billard.