The developer is now preparing to remove the three bombs that are believed to date from World War II.
Following the discovery of the explosives by a remotely operated vehicle, a 250-metre exclusion zone has now been set up around them.
Construction elsewhere on the site is continuing, RWE said, while the company works with contractors to identify the safest method of removal.
Previously, explosives have proved problematic for a number of wind farms, most significantly the Riffgat development in the German North Sea.
The 108MW project suffered heavy delays, with the first power flowing earlier this month — seven months later than planned — after the munition-strewn cable route had to be cleared.