A plea for the return of an historic artefact, people have dubbed "the key to Wellington City"

The pounamu key was stolen from the Museum of Wellington City and Sea around Thursday last week.

Richard MacLean from Wellington City Council says it has special significance.

"A ceremonial key that was presented to the mayor of Wellington when the town hall was opened in 1904."

People are being asked to report any sightings of the key, which is 12 centimetres long with gold features.