A New York restaurant operator has accused Seyfarth Shaw of missing key deadlines while representing the business in a lawsuit against its landlord, according to a complaint filed Tuesday in which Blue Dog At 399 Inc. seeks more than $40 million from the firm.

Blue Dog At 399, a venture by the Manhattan-based Blue Dog restaurant group, lodged legal malpractice allegations against Seyfarth and lawyer Ralph Berman, who previously served as counsel at the firm.