He found the plans in military files in the national archives and has published his discoveries in the book, Secrets and Treasures.
The files reportedly said initial testing was positive, however the project was ditched in early 1945. It was concluded that a single explosion would not be powerful enough to generate a tsunami, but a line of about 2 million kilograms of explosives about 8km from shore could create a giant wave capable of inundating a small city.
Mr Waru's book also has Defence records of UFO sightings, including drawings of unidentified aircraft, descriptions of aliens wearing "pharaoh masks" and alleged extraterrestrial writing, the Telegraph reported.
- nzherald.co.nz