A pilot was first to spot the drone, news agency NTB reports.
“It was the pilot in an aircraft who first observed the drone at a height of around 1,000 feet (300 metres), around five kilometres northeast of Oslo Airport. The pilot informed the control tower and the decision was made to halt air traffic until the situation was resolved,” Lasse Vangstein, press spokesperson with airport operator Avinor, told NTB.
The drone was first seen in airspace near the route of incoming flights at around 2:40pm on Tuesday, and it was incoming flights that were affected by the delay.
Landings resumed shortly after, at around 3pm.
“This is very serious. It is not permitted to fly drones so close to an airport and the altitude was also far higher than is permitted. The rules are there for a reason, and drone pilots must be responsible and respect them,” Vangstein said.
The incident will be reported to police, Avinor has confirmed.
SEE ALSO: VIDEO: Norway makes world's biggest chess board