The move was the latest development in an increasingly bitter and public spat over cable access for Mr Murdoch's Fox TV 24-hour news channel, which was launched this week.
The final merger between Time Warner and Turner Broadcasting is set to be approved by shareholders today.
In the lawsuit, Fox claimed the $7bn acquisition would create a monopoly because it "enhances Time Warner's ability and incentive to abuse its stranglehold over cable television systems to favour programming in which it has a financial stake".
The drama, which last month spurred Ted Turner to compare Mr Murdoch to Adolf Hitler, has drawn in almost the entire political establishment of New York state. Republican leaders - notably New York City Mayor Rudolph Giuliani and Governor George Pataki - have weighed in to support Mr Murdoch.
Mr Murdoch's News Corp, which owns Fox TV, is accusing Time Warner of reneging on an agreement to provide space for its all-news channel on Time Warner's cable system in New York City. Time Warner ended negotiations with Fox last week and opted to carry only Mr Turner's CNN, the market leader, and another entrant to all-day news, MSNBC, a joint venture between NBC and Microsoft.
Most observers believe that to survive the Fox channel must be seen in New York.
"We know we had an agreement," said Arthur Siskind, the lawyer representing Fox. "There are documents that reflect all the material terms in the agreement."
A condition of the federal approval of Time Warner's merger with Turner was that its cable system should carry at least one other news alternative to Turner's CNN.
In a statement of its own, Fox said the lawsuit alleged that a "conspiracy has taken place prior to the still-to-be-consummated merger" to freeze Fox out of the Time Warner cable network.
"The lawsuit is utter foolishness," said Richard Parsons, president of Time Warner, through a spokesman.Reuse content