Strauss-Kahn submitted to testing after his arrest more than a week ago. He denies the maid's allegations.
Testing was being performed on other items, said two people close to the investigation.
The forensic evidence is the first to link Strauss-Kahn to the woman - and it is also on track with what his lawyers have suggested would be his defence.
Strauss-Kahn's attorney, Benjamin Brafman, declined to comment yesterday, but at a court hearing last week he told a judge that forensic evidence developed in the investigation "will not be consistent with a forcible encounter". This has led to speculation that Strauss-Kahn's defence counsel would argue that the sex was consensual.
The New York Police Department and the Manhattan district attorney's office would not comment last night.
The one-time French presidential contender has been charged with a criminal sex act, attempted rape and sexual abuse and is free on $1 million bail, but under house arrest at a lower Manhattan apartment. Strauss-Khan, 62, has been accused of attacking the woman, 32, on 14 May in his luxury suite at the Sofitel hotel near Manhattan's Times Square. His lawyers insist he is innocent. He is due to enter a formal plea on 6 June.
On Monday, lawyers for Strauss-Kahn continued to search for new housing for their client as he awaits trial.
Strauss-Kahn has been staying at a temporary location under watch by armed guards with Stroz Friedberg, the same company that guarded disgraced financier Bernard Madoff. It remains unclear when he would be moved.
He resigned last Wednesday from the IMF.
His attorneys have described Strauss-Kahn as a loving father and family man.
And they say his actions after the attack was reported are not those of a guilty man eager for a quick escape. He left the hotel, had lunch and then phoned later to ask if he had left anything behind. When hotel staff said he had left his mobile phone, he told them exactly where he was: at John F Kennedy International Airport on a flight bound for Paris.Authorities arrested him at the airport.
Meanwhile, Ireland yesterday gave its support to French finance minister Christine Lagarde to become the next director of the International Monetary Fund.
The move comes as something of a surprise, given French-Irish tensions over the terms of Ireland's EU-IMF bailout.
Ireland's support adds to the growing European momentum for Ms Lagarde to succeed Strauss-Kahn.
"As finance minister (Lagarde] has responsibilities to hold the government's line in Paris, but she has been very sensitive to our concerns," said Ireland's minister for European affairs, Lucinda Creighton.
"She would be an excellent candidate, she's eminently qualified, and if she's nominated we're likely to support her."
Ms Lagarde herself has yet to say publicly whether she even wants the job.
Yesterday, the head of the OECD, Angel Gurria, seen by some as a potential candidate for the role, said choosing a woman to lead the Washington-based fund would benefit diversity, adding: "It's difficult to find somebody with more merit."
The IMF has never had a female managing director.