Citizens for Responsibility and Ethics in Washington, known as CREW, says DHS has until September 8 to hand over the Mar-a-Lago visitor logs.
"The public deserves to know who is coming to meet with the president and his staff", CREW Executive Director Noah Bookbinder said in their statement.
"We are pleased that, following this case, this information will become public for meetings in their private homes, but it must also be public meetings at the White House".
In March, Congressional Democrats introduced the MAR-A-LAGO Act (Making Access Records Available to Lead American Government Openness Act), to require the administration to publish a visitor log for the White House, as well as other places Trump regularly visits like Mar-a-Lago and Trump Tower. The logs are expected to be released in September. However, a federal court in NY has ordered the DHS to release Mar-a-Lago's records.
Trump, who has dubbed his Palm Beach, Florida club the "Southern White House", has been criticized for hosting foreign dignitaries and conducting official government business in public view at the club. DHS claims it has no records for visitors to Trump Tower, and litigation concerning the White House guest list is still ongoing.More news: Elon Musk: Governments better get ready for the robots
The court has asked for "records of presidential visitors", but it is not yet clear how broadly that is defined. The club is owned by the Trump Organization.
A spokesman told AFP that CREW plans to file a request for records about visitors to Trump's Bedminster, New Jersey property later this week.
The lawsuit, filed in January in the Southern District of NY, alleges Trump is violating the Constitution's emoluments clause whenever foreign entities lease Trump real estate or pay to stay at the Trump Hotel in Washington, D.C.
The Obama administration began voluntarily disclosing its visitor records in 2009 after CREW sued and won.
President Trump has spent 25 days at Mar-a-Lago since assuming the office of the president, according to a tracker by the New York Times.