Supreme Court justices, like other federal judges, are required to file an annual financial disclosure report which asks them to list gifts they have received. It was not clear why Thomas omitted the trips, but under a judiciary policy guide, food, lodging or entertainment received as “personal hospitality of any individual” does not need to be reported if it is at the personal residence of that individual or their family. That said, the exception to reporting is not supposed to cover “transportation that substitutes for commercial transportation” and properties owned by an entity.

Thomas has not yet responded to requests for comment.

The judge, who has sat on the Supreme Court for three decades, is seen as the most conservative judge on the court, and last year led the majority of judges who overturned the Roe v Wade ruling which guaranteed the right to abortion, to the delight of conservatives.

Demorats accused the judge of breaching ethical standards by not declaring the trips.

Illinois senator Dick Durbin said: “This behavior is simply inconsistent with the ethical standards the American people expect of any public servant, let alone a justice on the supreme court.

“Today’s report demonstrates, yet again, that supreme court justices must be held to an enforceable code of conduct, just like every other federal judge. The ProPublica report is a call to action, and the Senate judiciary committee will act.”

New York congresswoman Alexandria Ocasio-Cortez tweeted: “This is beyond party or partisanship. This degree of corruption is shocking – almost cartoonish. Thomas must be impeached. Barring some dramatic change, this is what the [chief justice John] Roberts court will be known for: rank corruption, erosion of democracy, and the stripping of human rights.”

Last month, the federal judiciary beefed up disclosure requirements for all judges, including the high court justices, although overnight stays at personal vacation homes owned by friends remain exempt from disclosure.

Last year, questions about Thomas' ethics arose when it was disclosed that he did not step away from election cases following the 2020 election despite the fact that his wife, conservative activist Virginia Thomas, reached out to lawmakers and the White House to urge defiance of the election results. The latest story will likely increase calls for the justices to adopt an ethics code and enhance disclosure of travel and other gifts.

In a statement, Crow told ProPublica that he and his wife have been friends of Thomas and his wife since 1996, five years after Thomas joined the high court. Crow said that the “hospitality we have extended to the Thomas's over the years is no different from the hospitality we have extended to our many other dear friends" and that the couple “never asked for any of this hospitality.”

He said they have “never asked about a pending or lower court case, and Justice Thomas has never discussed one, and we have never sought to influence Justice Thomas on any legal or political issue.”

ProPublica's story says that Thomas has been vacationing at Crow’s lavish Topridge resort virtually every summer for more than two decades. During one trip in 2017, other guests included executives at “Verizon and PricewaterhouseCoopers, major Republican donors and one of the leaders of the American Enterprise Institute, a pro-business conservative think tank,” ProPublica reported.

Crow wrote that he is “unaware of any of our friends ever lobbying or seeking to influence Justice Thomas on any case, and I would never invite anyone who I believe had any intention of doing that.”

The disclosure of the lavish trips stands in contrast to what Thomas has said about his preferred methods of travel. Thomas, who grew up poor in Georgia, has talked about enjoying travelling in his motorcoach and preferring “Walmart parking lots to the beaches.”