Sherpas have reportedly expressed concerns that vibrations caused by the helicopters could trigger avalanches.
Tourist flights are not allowed to places above Base Camp, which lies at an altitude of 5,634 metres, the BBC reported.
Helicopter companies have insisted though that their flights are allowed because they only fly over sights such as the Khumbu Icefall, which lies just above Base Camp.
Everest has not seen any expeditions for the past two years due to a series of disasters. In 2014 16 Sherpas died on their way to Camp One in an icefall, and at least 18 climbers died at Base Camp last year after a huge avalanche was triggered by the major earthquake.
Pasang Kaji Sherpa, a mountain guide with a military expedition team now on Everest, said: “The sightseeing helicopters are hovering above the Khumbu Icefall and making things difficult for us,” the BBC said.
"We worry that the vibrations caused by helicopters can crack ice blocks and snow packs on mountains overlooking the Khumbu Icefall. There is a deep-seated fear among Sherpa porters that they may be hit by avalanches this year as well and these helicopters are increasing fears," Pasang Kaji added.
The BBC claims it started to investigate whether sightseeing helicopters were permitted to fly to places such as the Khumbu Icefall, which prompted the Civil Aviation Authority of Nepal (CAAN) to then issue a circular to all airlines warning them not to conduct these flights.
"We have made it clear in the circular that sightseeing flights are simply not allowed in places higher than the base camp," Rajan Pokhrel, Deputy Director General of CAAN, told the BBC.
"Only rescue flights during emergencies are allowed in those areas and sometimes we allow special projects like skydiving when recommended by other government authorities."
Airline officials have reportedly insisted however that there is no danger.
Pabitra Karki, chairman of Airlines Operators Association Nepal (AOAN) said: “We fly 2,340 feet from above the ground and maintain at least 1km distance from the mountains so there is no way the vibration can cause avalanche.”
The BBC claims however that other sources at Base Camp have said the flights are becoming more frequent.
