About 200 Colombian soldiers are scouring mountains in the country's northern Antioquia province for holidaymakers taken hostage on Friday.
Police have blamed the Farc rebel group for the kidnap of at least seven people from a spa near the town of San Rafael.
No demands for the release of the group - none of whom is thought to be wealthy - have yet been reported.
The Colombian government had tried to persuade fearful citizens to holiday at home this year, say correspondents.
The government cancelled police leave and promised to put 120,000 security personnel on the ground.
"At the moment, troops are deactivating a field of antipersonnel landmines and continuing operations to find the hostage-takers," said the deputy provincial governor Jorge Mejia.
The security services have a large area to search and the police has complained that they were not informed of the kidnapping until Saturday morning - significantly delaying their response.
The police say a faction of Farc rebels swept into a spa near San Rafael on Friday, herding people into stolen vehicles.
Earlier reports said they took up to 40 tourists, but the state police chief later said seven people were abducted in an interview with the Associated Press.
No demands have yet been made for the hostages' release, but police say those taken are not wealthy.
The mass kidnapping comes as the statistics for the year were released showing a 38% fall in abductions.
Whilst the situation has improved markedly in national security, the rebels are still able to move around many parts of the country unmolested.
The BBC's Jeremy McDermott, in Antioquia, says a Christmas holiday has now turned into a nightmare for these hostages.
He says they will greet the New Year in captivity, unlikely to be released for some months - assuming their families can find the ransom the guerrillas will inevitably demand.
The Farc (Revolutionary Armed Forces of Colombia) kidnaps hundreds of people every year, to help to fund its 40-year campaign against the government.