Contractors working on the refurbishment of Wellington's Bowen State Building and Charles Ferguson Tower have discovered what's thought to be a time capsule, which could be more than 50 years old.
It was found last week by those working on the $200 million overhaul, and it will be opened up on Wednesday to see what's inside.
It came as a surprise to those working on the project, as there's no record at all of a time capsule being buried at the time of construction.
The Bowen State Building was designed and built by the Ministry of Works in the late 1950s, and opened in 1962, and the Charles Ferguson Tower was built in the mid-1970s.
Jenny Shipley's National Government sold the Bowen State Building in 1998.
Until recently, both buildings housed the Ministry for Social Development, which has since moved to new offices on The Terrace.
Bowen State Building was also home to popular state servant café and eatery called the Ministry of Food.
The capsule will be opened on site by Minister of Arts, Culture, and Heritage Maggie Barry at midday on Wednesday.
Ms Barry didn't want to comment on the discovery.
Precinct, the contractors, did not return calls.