U.S. Secretary of the Interior Ryan Zinke talks to reporters before departing Kanab Airport on May 10, 2017 in Kanab, Utah. Zinke has been in the state of Utah since Sunday talking with state and local officials and touring the Bears Ears National Monument.

Interior Department Secretary Ryan Zinke is being investigated by the Justice Department for possible use of his federal office for personal benefit, according to a new report Tuesday.

The probe of Zinke, which was detailed in a CNN article, came after the Interior Department's internal ethics watchdog referred the case to the Justice Department.

That watchdog, the Office of the Inspector General, has been conducting at least three probes of Zinke. It is not clear whether it was one of those investigations, or another case, that was referred to the Justice Department.

The OIG "only refers cases to the Justice Department when it has determined that there could be potential criminal violations," The Washington Post noted in its own article about the referral.

"As a general matter, the Justice Department does not confirm, deny or otherwise comment on the existence of investigations," a spokesman for the department said.

Spokesmen for the OIG and the Interior Department did not immediately respond to a request for comment.

One of the OIG's probes involves discussions Zinke had with the chairman of oilfield services company Halliburton, David Lesar, about a land development project in Montana, which Politico earlier this year revealed would include a parking lot on land controlled by a Zinke family foundation.

Another investigation relates to Interior's blocking of a request from a Native American tribe to open a casino in Connecticut.

The third probe relates to questions about the redrawing of boundaries of the Grand Staircase-Escalante National Monument in Utah, which removed property belonging to a Republican lawmaker in the state from the confines of the park.

Zinke, whose press office did not immediately return a request for comment from CNBC, told CNN when asked about the Justice Department probe: "They haven't talked to me. It will be the same thing as all the other investigations. I follow all rules, procedures, regulations and most importantly the law."

"This is another politically driven investigation that has no merit," Zinke said.