MGA Entertainment Inc. in a court filing has accused rival toymaker Mattel Inc. of fraudulently entering private showrooms so it could steal trade secrets and confidential information.

MGA, the Van Nuys toymaker that has fought to retain ownership its popular Bratz doll line, alleged that some employees of Mattel, the El Segundo maker of Barbie franchise, “willfully and deliberately misrepresented themselves” to gain entry into showrooms of rivals such as MGA, thereby acquiring a competitive advantage.

Referring to Mattel and its partners as a “racketeering enterprise,” the filing said “Mattel employees went to Kinkos and printed up fake business cards so that they could lie their way into the private showrooms of their competitors,” according to the complaint, which was filed late Monday.

“These eleventh hour claims are without merit,” said Mattel in its response. “They are a cynical attempt to deflect attention from MGA’s own wrongdoing. As the trial approaches, we expect more of the same. MGA prefers to try this case in the press; we look forward to defeating them in court.”

An MGA spokeswoman said the company had no comment on Mattel’s response.

The long-running dispute between the two local companies began when Mattel contended that the person who designed the Bratz dolls for MGA was still working for Mattel when he created them. Mattel eventually was awarded ownership of the Bratz line. However, the Ninth U.S. Circuit Court of Appeals last month said that ruling over-reached and “a significant portion – if not all – of the 2008 jury verdict and damage award should be vacated.” A new trial is set for January.

Mattel shares were up 58 cents, or 2.7 percent, to $22.29 in midday trading on the Nasdaq.