A House subcommittee has launched a broad investigation into the financial practices of television ministries and has asked some TV evangelists -- including Jim and Tammy Bakker, Jerry Falwell, Oral Roberts and Jimmy Swaggart -- to appear at a proposed public hearing on the matter within the next few weeks.

At least one of those televangelists, Falwell, said yesterday he is "very much in favor" of the probe and will be more than willing to testify. But two others, Billy Graham and Republican presidential hopeful Marion G. (Pat) Robertson, have sent word that they would not be able to attend because of prior commitments, although the panel conducting the probe hasn't scheduled a date yet.

The investigation by the House Ways and Means oversight subcommittee was triggered by recent disclosures surrounding the scandal-ridden PTL ministry, subcommittee staffers said yesterday. But the scope of the probe will extend well beyond the PTL affair, exploring such issues as the tax-exempt status of all TV ministries, their use of charitable donations and their financial accountability, congressional staffers say.

Another apparent goal of the probe, according to a recent letter by subcommittee Chairman J.J. Pickle (D-Tex.), is to examine the ticklish area of personal compensation or, as Pickle put it, what policies exist "for protecting against private inurement of ministry funds."

"Recent events surrounding the PTL . . . have cast shadows on television evangelical ministries which I feel need to be explored more fully in public," said Pickle in a recent letter to 11 of the leading televangelists.

Pickle added in the letter that "many members of Congress and individuals" have contacted him with questions about the activities of television ministries. "Frankly, I have not been able to answer their questions," added Pickle, a reference, according to subcommittee staffers, to the lack of scrutiny that has been accorded such ministries in the past.

Indeed, the investigation was described by some observers yesterday as unprecedented: the first in-depth congressional look inside the televised pulpit, a big-time and politically potent "industry" that generates hundreds of millions of dollars in tax-exempt revenues every year.

Staffers acknowledge they are treading on sensitive terrain. Even if the panel documents abuses at some ministries, there is no guarantee that Congress will be willing to do something about them, they say.

"Politically, it's dangerous getting into the whole church-federal government area," said a staffer, who asked not to be identified. "This is not something you can do without being sensitive to the First Amendment problems. I don't think anybody is dying to jump in and take on all the churches."

Nevertheless, Falwell, who took over PTL after the Bakkers resigned last March, said he believes that the television ministries should welcome the probe -- if only to rid themselves of the stigma attached to PTL, which stands for Praise the Lord or People That Love. "I would personally object to a great deal of government interference," said Falwell, who added that he plans to discuss the subject with Pickle at a private meeting in Washington Monday.

"But I think PTL graphically proves that we in the media ministry need a greater sense of accountability and openness . . . The point is made that we do need to police ourselves far more carefully. And we are open to listening to advice."

Falwell agreed that particular scrutiny is needed in the area of tax-exempt income. At PTL, for example, the tax-exempt ministry operates a Christian amusement park, Heritage USA, that includes features -- such as a giant water slide and a luxury hotel -- that appear indistinguishable from those at purely commercial enterprises, such as Disney World.

As part of a reorganization plan to be submitted shortly to a federal bankruptcy judge, PTL will be "breaking out" such activities into for-profit corporations, Falwell said. "When we compete with free enterprise, we should be listed as for profit and should pay taxes," he said.

It remains unclear how much cooperation the panel will get from the other high priests of televangelism. Subcommittee staffers said Robertson promised to send a representative and that Graham expected to be abroad for much of the summer.

But Graham was also quoted yesterday by newspaper columnist Cal Thomas, a former official of Falwell's Moral Majority, as saying he was "not too happy" about the hearing and that he is "always a little nervous about government interference in religious matters . . ."

Subcommittee staffers say California preacher Robert Schuller has agreed "to cooperate" but that they have heard nothing so far from the other recipients of the Pickle letter, including Swaggart, Roberts, John Ankerberg, Ernest Angley and, perhaps not surprisingly, the Bakkers, who are currently the subject of a Justice Department criminal investigation into allegations of tax fraud, mail fraud and other wrongdoing. The letter was mailed just before the July 4th holiday.

What of the possibility that the Bakkers, like Lt. Col. Oliver North, could take over the hearings from Congress and use the forum to generate public sympathy?

Falwell conceded that he finds the prospect more than a little frightening.

If the Bakkers agree to testify, Falwell said with a laugh, "I think I'll ask to come two days later."