Britain's Daily Mail newspaper on Wednesday reported details of an alleged court document filed by Mills McCartney containing accounts of mistreatment and drug use during the couple's four-year marriage.
"Our client will be defending these allegations vigorously and appropriately," law firm Payne Hicks Beach, representing Paul McCartney, said in a statement.
The 64-year-old rocker and 38-year-old anti-land mine campaigner announced their separation in May and have begun divorce proceedings in an increasingly acrimonious split. They have a 3-year-old daughter, Beatrice.
Mills McCartney's spokesman, Phil Hall, described the divorce proceedings as "highly confidential" and said he could not confirm whether the document cited in the report was genuine. He said Mills McCartney had been "shocked" by the Daily Mail's story.
The newspaper did not reveal how it had acquired the document, which alleges that McCartney once attacked his wife with a broken wine glass, stabbing her in the arm and causing profuse bleeding. It also claims that he used illegal drugs and drank to excess.
The newspaper reported that the purported 13-page submission also alleged that McCartney had pushed his estranged wife into a bathtub while she was pregnant with their child.
It said the document, said to be filed by Mills McCartney in response to the former Beatle's divorce petition, lodged in July, also claimed McCartney had later objected to his partner breast-feeding their daughter.
The newspaper quoted the alleged court papers as saying McCartney had told his wife "they are my breasts."
It reported that the document alleged McCartney had grabbed his wife's neck and started choking her during a trip to the U.S. in 2003 and on an earlier occasion pushed her over a coffee table.
Mills McCartney is reported to claim in the legal papers that in late 2005 her husband forced her to cancel surgery for two months, as it interfered with their holiday plans.
Mishcon de Reya, the law firm representing Mills McCartney in the divorce, said it would not comment on "leaked or allegedly leaked documents."
It said it could not confirm whether or not a response to McCartney's divorce petition had been lodged with a court.
"Mills McCartney stands by everything that has been filed at court on her behalf and intends to prove its truth in due course should this be necessary," the law firm said in a statement.
The Associated Press obtained a document that appeared to be a divorce court filing, containing details that matched those reported by the Daily Mail. The authenticity of the document could not be confirmed.
Paul McCartney's law firm said the musician "would very much like to respond in public and in detail to the allegations made recently against him by his wife and published in the press but he recognizes, on advice, that the only correct forum for his response to the allegations made against him is in the current divorce proceedings."
"Our client is saddened by the breakdown of his marriage and requests that his family is allowed to conduct their personal affairs out of the media spotlight for the sake of everybody involved," the statement added.