Toho spokesman Makoto Hanari said a lawsuit was filed Tuesday in a California court, but declined to discuss details. Voltage Pictures President Jonathan Deckter declined to comment.
Toho created Godzilla with its 1954 classic film, owns the rights to the character and licenses it for figures and video games, as well as Hollywood remakes, such as last year's "Godzilla" movie directed by Gareth Edwards.
The current complaint is over buzz that Los Angeles-based Voltage is trying to create for director Nacho Vigalondo's upcoming film "Colossal" that Toho says uses Godzilla images without permission or payment.
Production for the film has not yet begun, and it is unclear whether Godzilla will be in the finished product.
But the lawsuit accuses Voltage of using the Godzilla image in emails and other promotion activities, allegedly to raise funds for the film.
Founded in 2005, Voltage Pictures is an international finance, production and distribution company, with a library of about 100 films, including "The Hurt Locker."
In an August 2014 interview with Film Divider, an online publication about movies, Vigalondo said he planned to make a Godzilla film, but one that depicts the experience of being in the Godzilla rubber suit, as the monster was initially portrayed.
"It's going to be the cheapest Godzilla movie ever, I promise," said Vigalondo, who directed "Open Windows."
Toho's reptilian monster mutated from nuclear-weapons testing and appealed to the emotions of Japanese people traumatized by the atomic bombings of Hiroshima and Nagasaki. Over the decades, the creature wowed fans by stomping on cities, crashing new buildings and fighting other monsters.
Toho killed Godzilla in 2004, with the 28th film in the series, but has decided to shoot a new film after the Hollywood remake proved a hit.
Follow Yuri Kageyama: http://twitter.com/yurikageyamaSuggest a correction