South African climber was in police custody in Nepal's capital on Wednesday after he attempted to scale Mount Everest without obtaining the mandatory permit, an official said.
Ryan Sean Davy from Johannesburg had been caught by a mountaineering official at the Everest base camp earlier this month and his passport was seized.
He agreed to trek down the mountain and surrender to the Tourism Department in Kathmandu, where he was detained on Tuesday.
Tourism Department chief Dinesh Bhattarai said Davy was in police custody for questioning but a decision on his case has not been made. He could be fined $22 000 and banned from visiting Nepal and climbing mountains for years.
He has not been allowed to speak to media since his detention on Tuesday.
Permits to climb Everest cost $11 000 per person. The money helps the impoverished country fund government services, including rescues of climbers stricken by injuries and illness while on the mountain.
Hundreds of climbers will try to reach the top of Everest this month, when weather conditions are most favorable on the world's highest mountain.
The Tourism Department issued a record 371 permits this year to people who will attempt to climb the mountains, and an equal number or more Nepalese Sherpa guides will accompany them.
The first group of climbers reached the summit earlier this week. However, weather near the summit was deteriorating, forcing other climbers to wait.
The increased number of climbers this year likely includes people who returned after being unable to climb in 2014 and 2015.
The 2015 season was scrapped after 19 climbers were killed and 61 injured by an avalanche at the base camp triggered by a massive earthquake. In 2014, an avalanche at the Khumbu Icefall killed 16 Sherpa guides.
Climbers who had permits for the 2014 season were allowed to receive a free replacement permit until 2019, while climbers with 2015 permits were given only until this year.
Davy uploaded a video to his Facebook page, saying "I'm just about to go in to the Department of Tourism and I have no idea of the outcome regarding my Everest no permit climb. In the meantime I've compiled this little video of some of the events as they unfolded during the course of my awesome adventure."
South African who attempted to climb Mount Everest without permission has been arrested in Nepal where he faces a $22 000 fine - double the cost of the permit he was trying to avoid.
Ryan Sean Davy handed himself in to authorities in Kathmandu on Tuesday after being caught last week hiding in a cave near Everest's base camp without a permit.
The 43-year-old began swearing and threatening officials from the tourism department during questioning and was arrested under Nepal's strict public order laws, Tourist Police Inspector Tulasha Khatiwada told AFP.
He is now in custody and will appear in court next week to face charges related to his Everest attempt and possible additional offences over his conduct during the investigation.
"He will be fined and deported as per the Tourism Act of Nepal. He may face further penalty for misbehaving with the police," director of the tourism department Dinesh Bhattarai said.
Foreigners have to pay the Nepal government $11 000 for permission to climb the 8 848m (29,029-foot) peak - a major earner for the impoverished country.
Under Nepali law, climbers caught without the mandatory permit are fined $22 000.
Davy could also be blacklisted from the Himalayan nation for five years, or face a 10-year climbing ban when he appears in court next week.
The South African who describes himself on social media as a film director and producer was caught a short distance from Everest base camp and was ordered off the mountain.
He had pitched a tent away from the other climbers to try and dodge government officials who monitor all Everest ascents.
He told officials he had climbed alone as far as camp two - at 6 400 metres - to acclimatise in preparation for a solo summit bid.
His antics have angered many in the close-knit climbing community, who say the South African would have put himself and others in danger if he had attempted to reach the summit alone.
He did not have any agency to look out for him or call for rescue if anything happened. Other teams would have to come to his rescue, and would be exposed to unnecessary dangers, said Ang Tsering Sherpa, head of the Nepal Mountaineering Association.
The system of permits and guides is there for a reason.
Davy was caught not far from where more than 1 000 mountaineers and support staff have gathered for the busy spring climbing season.