"The injured have been sent to Kathmandu for treatment", Adhikari said.
The Twin Otter aircraft crashed into the helicopter at Tenzing Hillary Airport at Lukla, known as the gateway to the world's highest mountain, 125 km (78 miles) northeast of capital Kathmandu.
The Summir Air plane was reportedly en route to Kathmandu from Lukla.
Three people have been killed and four injured after a plane crashed during takeoff near Mount Everest, according to reports.
An airport official spoke to Straits Times, saying: "The plane slipped towards the helipad during take-off and collided with two helicopters".
Police spokesman Uttam Raj Subedi said: "The co-pilot and a policeman died at the crash site".
"We have received preliminary information that the plane taking off from the airport lost control and hit the chopper", Chief District Officer (CDO) of Solukhumbu Narendra Kumar Rai told Setopati.
Both airlines are private companies serving locals and tourists in the remote areas of Nepal.
The accident happened at Lukla airport which is the main gateway to the Everest region and is reputed to be one of the most hard in the world for landings and take-offs.
Hundreds of foreign climbers head to Mount Everest in April during the commercial expedition season, which lasts until May. The airfield is notorious for its short runway and perilous approach, sitting at an elevation of over 2,800 meters.