The Interior Department is preparing to open 1 million acres in the national wildlife refuges to oil and gas exploration, reversing a 25-year-old federal policy and probably starting another vocal confrontation with conservation groups and Interior Secretary James G. Watt's congressional foes.

The new policy is reflected in rules drawn up by the Bureau of Land Management that are designed to streamline leasing procedures under Watt's five-year program for opening more federal lands to oil and gas production.

The regulations have not been released, but regional directors of Interior's Fish and Wildlife Service were told last month that the rules will allow leasing on "acquired-land" refuges in the lower 48 states as long as the proposed development "is compatible with the purposes for which the refuge was established."

The affected refuges are those that were purchased by the federal goverment from private owners and on which energy development has not been banned specifically.

Fish and Wildlife Service officials said yesterday that the decision could lead to oil and gas leasing on about 1 million of the 12.8 million acres of wildlife refuges in the 48 contiguous states. Oil and gas exploration in Alaska is governed by the Alaska Lands Act of 1980.

An Interior spokesman said yesterday that the change was made on the basis of a 1981 decision by the Interior Board of Land Appeals, which held that acquired-land refuges were open for leasing unless they had been established to protect "all species of wildlife."

Most refuges are set aside to protect migratory waterfowl or the wintering or nesting grounds of a particular species, such as the whooping crane.

Interior spokesman Harmon Kallman said the new rule was not the equivalent of opening wilderness lands to leasing, an earlier Interior initiative that brought the wrath of Congress down on Watt.

"That is not exactly virgin ground," he said, noting that some refuges already are open to timbering, grazing and mineral development. In some cases, oil and gas operations are in place as a result of private claims that predated establishment of the refuge.

But the Wilderness Society said a recent survey, conducted by Interior and the American Petroleum Institute, showed that those operations have caused problems on the refuges, including oil spills, wetlands damage, habitat destruction and poaching by company employes.

"If we value the integrity of our land and the protection of threatened and endangered species, we cannot allow Secretary Watt to exacerbate an already critical situation," said Charles M. Clusen of the society.

According to the Fish and Wildlife Service, more than 144 lease applications have been received since the land appeals board issued its ruling. They involve 614,876 acres on 46 refuges in 24 states.

Among the most popular targets for developers are the Umatilla refuge on the Washington-Oregon border, where 20 applications are pending, and the Okefenokee refuge in Georgia, which drew 18 lease applications involving more than 170,000 acres.

Energy development on refuges was prohibited by the Eisenhower administration, which decided that recreational uses, such as camping and fishing, might be compatible with wildlife protection, but oil and gas development was not.