The New York Post said 1MM filed the lawsuit in Manhattan Supreme Court and accused DNA of hiring one of its former bookers, Vivien Wang, despite a non-compete agreement.
The lawsuit claims 1MM model Denisa Dvorokova is following Wang to the other agency, The Post said.
Although Wang signed an agreement stating she wouldn't work for any of 1MM's competitors for a year, she was allegedly working at DNA within a month of her departure from 1MM in May, the suit said.
"One Model honors its contracts and takes very seriously the contracts it enters into with its employees," company lawyer Ken Sussmane told The Post.
The newspaper said a DNA representative didn't return its call for comment before its story was published.