Parts of Munich airport were briefly sealed off after a laptop set off an explosives detector and its owner, who is still on the run, fled into a secured area.

The fourth floor of the airport's Terminal II, used for flights within Germany and Europe's passport-free Schengen Area, was evacuated and all docked planes were temporarily grounded.

Berti Habelt, a spokesman for the federal police, cautioned that the scanner could have been set off by chemicals such as perfumes, and that the man may simply have been in a hurry to catch his plane.

"It is not 100 per cent clear that there were in fact explosives," he said.

"The explosives detector was alerted by a laptop, and as a result should have been checked again.

"But at this point the male passenger left the security area into a secured area.

"Searches are still taking place for this person. In the meantime we have examined security camera footage."

Airports around the world have been on high alert since a Nigerian man was arrested and accused of trying to blow up an airliner over the US on December 25 with explosive chemicals.