In a major development that 600,000 doctors have been waiting almost a year for, the 11th Circuit Court of Appeals ruled Wednesday that the doctors can pursue their class-action lawsuit charging the major health insurers with engaging in a racketeering criminal conspiracy to delay or deny payments to the doctors.

“This is huge,” said Harley Tropin, co-lead counsel for the doctors and more than a dozen state medical associations that are suing Humana, UnitedHealthcare, Prudential, PacificCare and Wellpoint.

Two other insurers, Aetna and Cigna, have already reached settlements valued at $470 million and $540 million.

The insurance companies had appealed the class-action certification that had been made by U.S. District Judge Federico Moreno in Miami in September 2002.

Among other arguments, the insurers said the lawsuit could be financially disastrous. The appellate judges shrugged off that idea.

“It would be unjust to allow corporations to engage in rampant and systematic wrongdoing, and then allow them to avoid a class action because the consequences of being held accountable for their misdeeds would be economically ruinous,” wrote Judge Gerard Tjoflat.

The central complaint of the doctors and medical associations is that the insurers used similar computerized programs that automatically stalled or denied payments.

The three appellate judges affirmed the racketeering class action, but recommended Moreno “reconsider the precise scope of the classes” and reversed his class-action certification of most of the state-law claims.

In a prepared statement, the insurers Wednesday applauded the courts ruling on the state claims.

“With respect to the federal claims, we continue to believe that these claims are not appropriately handled as a class action,” said Kent Jarrell, spokesman for the insurers. “Ultimately, with respect to these federal claims, we are confident that we will win at trial based on both the heightened standard of proof and the evidence.”

Speaking for the doctors, Tropin said the bulk of the case is still intact. “This will allow the 600,000 doctors and the medical associations to finally bring the case to a jury and Judge Moreno.’’

The trial is scheduled to begin next March, but the appellate judges warned that Moreno has a complicated road ahead.

“Given the number of parties involved in this case, it threatens to degenerate into a Hobbesian war of all against all. Nevertheless, we feel that the district court _ a veritable Leviathan _ will be able to prevent the parties from regressing to a state of nature. One can only hope that, on remand, the proceedings will be short, though preferably not nasty and brutish.”