WASHINGTON >> U.S. Supreme Court Justice Clarence Thomas took additional undisclosed travel paid for by billionaire benefactor Harlan Crow that the conservative justice failed to disclose, the Democratic chair of the Senate Finance Committee said today.

Thomas and his wife took round-trip air travel between Hawaii and New Zealand in November 2010 aboard Crow’s private jet, according to Senator Ron Wyden, citing international flight records obtained by his committee.

Thomas has come under criticism since last year from congressional Democrats and others for failing to disclose gifts from Crow, a Texas businessman and Republican donor, including trips on a yacht.

A Supreme Court spokesperson and an attorney for Thomas did not immediately respond to requests for comment today.

The justice previously defended his omission of Crow-funded luxury trips from his disclosure forms by saying he believed they were “personal hospitality” and thus exempt from disclosure requirements, and called his nondisclosure of a real estate transaction involving Crow inadvertent.

Wyden cited the international flight records, maintained by the U.S. Customs and Border Protection agency, in an eight-page letter to Crow’s attorney seeking details on the businessman’s relationship with Thomas. It is part of what Wyden called his committee’s investigation “into the tax treatment of the use of Mr. Crow’s superyacht and private aircraft.”

Wyden first requested such information last year after the news outlet ProPublica reported on the justice’s failure to disclose luxury trips and real estate transactions involving Crow.

“Neither Mr. Crow nor Justice Thomas have disclosed the full scale of Thomas’s use of (Crow’s yacht) Michaela Rose and private jets courtesy of Mr. Crow, even as the Congress continues to uncover additional international private jet travel with Mr. Crow that Justice Thomas failed to disclose on his ethics filings,” Wyden said.

Crow spokesperson Michael Zona said that Crow’s attorneys had previously addressed Wyden’s inquiries, which Zona called baseless and “only intended to harass a private citizen.”

“Mr. Crow and his businesses are in good standing with the IRS. He has always followed applicable tax law as advised by national accounting firms who serve as his tax advisors,” Zona said.

“It’s concerning that Senator Wyden is abusing his committee’s powers as part of a politically motivated campaign against the Supreme Court,” Zona added.

Democrat Dick Durbin, chair of the Senate Judiciary Committee, in June said Thomas took at least three other trips funded by Crow that the justice also failed to disclose.

Facing criticism after revelations involving Thomas and other justices, the Supreme Court last November adopted its first code of conduct. Congressional Democrats and other critics have said the code does not go far enough to promote transparency, continuing to leave decisions to recuse from cases to the justices themselves and providing no enforcement mechanism.

White House spokesperson Andrew Bates said the information released by Wyden strengthens the case that President Joe Biden made last week for “common-sense reforms” to the Supreme Court.

Biden last month proposed sweeping changes, including term limits of 18 years and a binding code of conduct for the life-tenured justices. The Democratic president said the revamp was needed to rein in a conservative-led court that was undermining established civil rights principles and protections. Opposition by Republicans in Congress means the proposals have little chance of enactment.

Additional reporting by Nate Raymond in Boston.