PHOENIX — A federal appeals court refused Thursday to bar prosecutors from enforcing Arizona’s new employer sanctions law while they hear arguments on its legality.

 The judges of the 9th U.S. Circuit Court of Appeals rejected arguments by lawyers for business groups and their allies that they should not let prosecutors investigate — and potentially bring charges against — companies who are accused of knowingly hiring undocumented workers.

 In an unsigned order, the judges said they considered the arguments by challengers that they would suffer irreparable harm and the likelihood the foes ultimately will succeed in convincing the court to overturn the ruling earlier this month by U.S. District Court Judge Neil Wake that the law is constitutional.

 “We conclude the appellants have not shown that the case warrants a grant of temporary relief during the pendency of these expedited appeals,’’ the order states.

 But the judges did agree to rush the case — at least by appellate standards — with all the legal arguments by both sides filed by the middle of May.

 Farrell Quinlan, a spokesman for some of the business groups that are contesting the legality of the statute, said his clients are disappointed. But Quinlan said that accelerated hearing schedule means there actually could be a final ruling as early as the end of the summer.

 In the interim, that means Arizona employers must check the legal status of all new workers through the federal government’s E- Verify system. Business groups said the financial cost of compliance, ranging from buying computer equipment to having someone do the checks, is an unfair burden.

 That argument was rejected by Wake.

 The bigger issue for companies is the provision of the law, which took effect Jan. 1, which allows a state judge to suspend any and all licenses and permits to do business of any firm found guilty of knowingly hiring anyone not legally entitled to work in this country. A second conviction within three years puts the company out of business.

 David Selden, one of the lead attorneys in the case, has argued that the law is an impermissible intrusion by the state into the exclusive power of the federal government to regulate immigration.

 Wake acknowledged federal law bars states from imposing civil fines and criminal penalties against companies because they hire undocumented workers. But he pointed out that federal law specifically says states can use their licensing and similar laws to punish errant companies.

 And Wake said the fact that suspending or revoking a company’s ability to stay in business could be more serious than a fine is legally irrelevant.

 Selden said the fact he was unable to get an injunction does not mean the court is unlikely to accept his arguments that the law is invalid.

 “To get an emergency injunction you’ve got to tip the scales very heavily at the outset in your favor,’’ he said.

 “Obviously we would have preferred to win this motion,’’ Selden continued. “But we’re still optimistic that when the litigation is over this will all be declared unconstitutional.’’

 Joining in the challenge have been groups like the American Civil Liberties Union and Chicanos Por La Causa who have argued that businesses would be less inclined to hire Hispanics out of fear one might prove to be undocumented.