Eleven climbers have been reported dead or missing in the past 10 days. Briton Robin Haynes Fisher, 44, died minutes after reaching Everest's summit on Saturday, while an Australian climber has “critical health problems” after being taken off the mountain.
Nepal's tourism authority has denied accusations that the rise in Mount Everest deaths is solely due to overcrowding.
The department's director general Dandu Raj Ghimire told the BBC other factors including adverse weather conditions had also contributed.
Eleven climbers have been reported dead or missing in the past 10 days. Briton Robin Haynes Fisher, 44, died minutes after reaching Everest's summit on Saturday, while an Australian climber has “critical health problems” after being taken off the mountain.
Photos show long queues near the summit as record numbers climbed the mountain in May.
Ghimire said 381 people had ascended Everest this spring but as periods of fine weather had been short, the number of people on the routes had been "higher than expected".
A local tour organiser told AFP that one Indian climber died of exhaustion after being "stuck in traffic for more than 12 hours".
"Mountaineering in the Himalayas is in itself an adventurous, complex and sensitive issue requiring full awareness yet tragic accidents are unavoidable," Ghimire said.
The crowding on the mountain was highlighted in a photo taken last week by Nirmal Purja, a former Gurkha soldier, of a long queue of climbers heading for the summit.
The photo by the head of the Project Possible charity aiming to climb the 14 8000-metre plus peaks in the world in seven months has gone viral from his @nimsdai Twitter account.