Believers walked in a procession, singing and carrying banners, one saying "Christ King of the Universe" as they made their way to the huge statue overlooking a plain in the western Polish town of Swiebodzin, the news agency PAP reported.
Another sign bore the words "King of Kings" on a banner shaped like a king's crown.
People in Swiebodzin boast that the statue with outstretched arms dubbed "Christ the King" is the world's largest, rising even higher than Rio de Janeiro's famous Christ the Redeemer.
"The monument is a visible sign of faith in Christ," said Bishop Stefan Regmunt, one of several clerics who led outdoor ceremonies at the site.
Local businesspeople hope the monument, which was completed on November 6, will attract tourists and pilgrims and give the area an economic boost. But some Poles accuse the priest who created it of megalomania and say its grandiosity violates Christ's spirit of humility.
The statue itself is 33m high - one meter for every year Jesus lived. A golden crown adds two more meters, while a huge mound it sits on takes the whole height to just over 51m.
Rio's statue is 38m tall.