A co-pilot hijacked an Ethiopian Airlines flight to seek asylum in Switzerland, surrendering to police at Geneva airport after jumping out of a cockpit window and scrambling down an emergency rope.

The plane's second-in-command, named by Ethiopia as Hailemedhin Abera Tegegn, 31, took control of ET-702 from Addis Ababa on Monday when the pilot left the cockpit to use the lavatory.

Tegegn then sent a coded signal announcing he had hijacked his own aircraft, which was scheduled to land in Rome.

French and Italian jets were scrambled by NATO to escort the plane. The AFP news agency quoted a Swiss airforce spokesman as saying Swiss jets remained on the ground because they only flew during business hours.

"Switzerland cannot intervene because its airbases are closed at night and on the weekend," Laurent Savary told the agency, adding: "It's a question of budget and staffing."

After the plane landed in Geneva, the unarmed Hailemedhin jumped out of a cockpit window and did not harm passengers or crew, police spokesman Pierre Grangean said.

"Just after landing, the co-pilot came out of the cockpit and ran to the police and said, 'I'm the hijacker.' He said he is not safe in his own country and wants asylum," Grangean said.

The plane could later be seen with a knotted yellow rope dangling from an open cockpit window.

After the co-pilot was detained, police escorted passengers one by one, their hands over their heads, from the taxied plane to waiting vehicles. Officials said there was no risk to passengers or crew at any point.

The Ethiopian government, which owns the airline, said Tegegn had worked there for five years and was, according to spokesman Redwan Hussein, "medically sane".

However, he said the Tegegn's actions represented "a gross betrayal of trust that needlessly endangered the lives of the very passengers that a pilot is morally and professionally obliged to safeguard".