Some federally subsidized nonprofit groups contracted to provide various educational activities to the public have strayed from their mission by offering weddings, wine-tasting events and yoga classes, an audit by the Interior Department’s Office of the Inspector General found.

The National Parks Service, which partnered with the groups to operate Residential Environmental Learning Centers at various parks, failed to provide proper oversight and ensure the activities and services "complied with agreements, statutes, and regulations," an OIG report said.

The report said the NPS consistently failed to use the correct type of agreement or legal vehicles to authorize the RELCs. Some organizations received thousands of dollars in federal funds while providing expensive services like high-dollar wedding packages, private hiking tours and other offerings.

CALIFORNIA REDWOOD TREE FALLS, KILLS HIKER AT NATIONAL PARK

One group, NatureBridge, offered wedding packages ranging between $13,000 to $18,000 at Olympic National Park in Washington.

"As a nonprofit, public benefit organization, all dollars raised by NatureBridge, including from generous donors and weddings, are invested in delivering transformational environmental education programs in national parks to America’s youth," the organization said in an statement emailed to Fox News.

It said it was responsible for the maintenance of NPS facilities in which it operates, thereby "decreasing the maintenance backlog for the National Park Service."

Other activities cited in the report include a private hike to a lighthouse -- with live music, a silent auction and refreshments -- and chef-crafted meals for $250 to $365 per person. Other learning centers offered yoga classes for up to $365 per person.

“National parks provide substantial support for these centers in terms of staff time and facility usage, but taxpayers get nothing in return for these subsidies,” said Jeff Ruch, executive director of the nonprofit Public Employees for Environmental Responsibility. “Given the huge maintenance deficit facing our national parks, those entities that benefit from park facilities should be required to pay their fair share.”

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A request for comment from the National Parks Service was not immediately returned Thursday.

The OIG made a dozen recommendations to improve oversight of the programs, including developing a system specifically outlines which activities can be authorized within RELC agreements and ongoing monitoring.