According to the airport website, queues at airport security on Friday morning were around half an hour long, with the airport advising travellers to expect long waiting times.
In a message on the airport website, it advises passengers to arrive two hours before departure if flying within Schengen, or three hours before if travelling outside of Schengen.
According to the Ritzau news wire, the long queues are due to "supplementary requirements" put in place by Denmark's Civil Aviation and Railway Authority, Trafikstyrelsen.
"The Civil Aviation and Railway Authority carries out constant checks of whether the airport is living up to security requirements in a long list of different areas," the authority said in a comment to Ritzau on Thursday evening. "As a result of our checks the authority has identified situations which mean that the airport needs to carry out some temporary additional checks at security."
It did not provide information on the reason behind the checks.
According to Danish public broadcaster DR, which alongside TV 2 has journalists on-site at the airport this morning, the queue at 7am stretched all the way from security control to the airport's metro station.
The extra controls are expected to continue throughout the weekend "as a minimum," the airport's head of communications Lise Agerley Kürstein told Ritzau.
Copenhagen Airport is the largest airport in Scandinavia, serving much of Denmark and southern Sweden. While Denmark's autumn holidays, efterårsferie, have already been and gone, Sweden's start next week, which means the airport could be busier than usual.