Justice Department officials and the three major television networks are preparing a proposal to set aside a federal court order that limits the amount of programming the networks can produce, sources said today.

If successful, the effort could give the networks a much bigger share of the $3 billion prime-time-TV production business, which now is controlled by the Hollywood film industry and independent producers.

By making a deal with the Justice Department, the networks hope to bypass Federal Communications Commission rules designed to assure that prime-time programming is not controlled exclusively by the networks.

An FCC proposal to lift what are known as the Financial Interest and Syndication Rules has run into fierce opposition from independent producers, who say it could give the networks a virtual monopoly over what is seen on prime-time TV.

"They own all the theaters, so that would put the entire production community at a disadvantage," said Mel Blumenthal, executive vice president of MTM Enterprises Inc., a major independent television production company.

The Justice Department has endorsed lifting the FCC rules. But about 100 House members are backing legislation that would prevent the commission from altering the rules. "It sounds like a back-door way to have a major financial interest in their shows," said a congressional source when asked about the networks' effort.

The networks' influence and investment in prime-time shows now is limited by both the FCC rules and a series of court orders issued after the Justice Department in 1972 sued the networks for allegedly violating antitrust laws and monopolizing program production.

The networks settled the lawsuits by signing a series of consent decrees in which they agreed to limit their stake in TV programing. Now the networks are trying to overturn those decrees and have held a series of closed-door meetings with Justice Department officials in recent weeks.

Sources close to the talks said the government and the networks have agreed on a bid for a modification of the decrees, and a draft of the government's position is expected to be circulated shortly. "Their comments are being translated into a document which would represent a modified decree," said one source.

Such a plan, however, would require approval of the federal judge in Los Angeles who oversees the decrees and probably also would require a period for public comment before approval.

"A great many people, particularly the Hollywood studios, will do everything they can to excerise their rights in court," a leading studio attorney said.

Several network officials refused substantive comment today; Justice Department lawyers could not be reached.

The consent decrees limiting the networks' prime-time programing were put into final form just three years ago. They stem from suits filed by the Justice Department during the Nixon administration against American Broadcasting Cos. Inc., CBS Inc., and National Broadcasting Co.

The initial lawsuits were dismissed in 1974 after allegations that they were politically motivated. But when the Ford administration came to power a month later, similar suits were filed anew.

NBC settled the suit brought against it in 1977, and CBS and ABC followed in 1980. Terms of the virtually identical settlements are similar to the FCC rules that bar the networks from acquiring syndication rights and financial interests in most television programming.

The court orders specifically limit the weekly network production of the programs to eight hours during daytime, 11 hours during fringe times and 2 1/2 hours a week of prime-time shows. The decrees also limit the networks' ability to hold exclusive rights to particular programs and otherwise restrict their participation in program production.

If the decrees were set aside, the networks still would need FCC approval to get into the lucrative business of syndicating reruns or new programs to local television stations.

But sources indicate that the Justice Department is willing to increase substantially the number of hours of in-house programs that the networks can broadcast. Government officials also have indicated that they are willing to lift most of the financing constraints in the decree.