The Justice Department has decided to launch a formal criminal investigation into the PTL ministry focusing on allegations of tax fraud and other wrongdoing during the reign of its exiled founders, televangelists Jim and Tammy Bakker, law enforcement sources said yesterday.

The investigation will be conducted by the department's tax division in concert with Vinton D. Lide, U.S. attorney in Columbia, S.C., sources said. Evidence compiled by the tax division and the Internal Revenue Service will be presented by Lide's office to a federal grand jury, the sources said.

The decision to initiate the investigation represents a major escalation of federal inquiries into the embattled charismatic ministry. The IRS and the U.S. Postal Service had already begun their own probes following charges of exorbitant million-dollar salaries for the Bakkers, extravagant life styles and missing funds during the Bakkers' tenure -- all products of tax-exempt contributions to an ostensibly nonprofit church organization. Until now, however, Justice Department officials have been reluctant to initiate a formal criminal probe, saying they first wanted to await the results of a three-year IRS tax audit of the ministry.

Melvin Belli, the flamboyant San Francisco attorney now representing the Bakkers, said yesterday that the Bakkers have nothing to hide and will be more than willing to meet with federal investigators.

"I'm sure they can straighten out any questions the government has to ask them -- and if the government has any religion, I'm sure they'll be able to recognize kindred souls in Jim and Tammy," said Belli.

Belli said he has not yet reviewed specific charges of financial wrongdoing with the Bakkers. Nevertheless, he began yesterday to construct what many have long felt is likely to be the couple's main defense against any possible criminal charges: that Bakker was primarily a spiritual leader who left the running of his ministry's $129-million-a-year finances to deputies.

"Jim was never a money man," Belli said. "He was a minister. He's not concerned with worldly goods ... All he was doing was preaching and asking people to send money."

Bakker resigned from PTL and turned it over to the Rev. Jerry Falwell in March after confessing to a 1980 sexual encounter with a former church secretary. Jerry Nims, the new PTL chief executive officer appointed by Falwell, said yesterday that he was "gratified" by the Justice Department decision, pledging the ministry's full cooperation with the probe.

Details as to when Lide will begin presenting evidence to a grand jury could not be learned yesterday. A spokeswoman in his office said Lide was out of town and could not be reached for comment. But department sources noted that the decision to give the tax division the lead role in the case could end up restricting the scope of the probe. Nearly two years ago, the IRS first recommended stripping PTL of its tax-exempt status after finding that the Bakkers had received nearly $1 million in excessive compensation during the years 1980 and 1983. Since then, there have been numerous other allegations involving PTL, including mail fraud, wire fraud and extortion, which some officials said are not likely to be relevant to the tax division.

But a Justice official dismissed those concerns yesterday, saying that the criminal division's fraud squad was prepared to assist in the investigation if needed.