PHOENIX — The state Court of Appeals on Tuesday blocked enactment of a new law allowing candidates to take a lot more money from donors.

In a brief ruling, the three-judge panel essentially accepted arguments by the attorney for the Citizens Clean Elections Commission that there is reason to believe the sharply higher limits, approved earlier this year by the Republican-controlled Legislature, are illegal and must be halted immediately.

Judge Randall Howe, the presiding judge who signed the order, did not explain which of two legal theories advanced by attorney Joe Kanefield the court was accepting. He promised a full ruling later.

Most immediately, the order directs Secretary of State Ken Bennett, as the state’s chief election officer, not to enforce the law. That immediately limits candidates to the lower figures that were in place before Sept. 13.

It’s unclear what happens to the money above those limits candidates accepted during the month the law was in effect.

Kanefield said, generally speaking, court rulings are retroactive, which would force candidates to refund anything they got above the old limits.

But Tom Collins, the commission’s executive director, said he’s not going to be pursuing candidates — at least not yet. “Whatever somebody did in the preceding last month, they did it,” he said. “It’s done.”

Collins said he wants to wait for the court’s written opinion before deciding whether to seek refunds for contributions. He said his most immediate concern is getting the word out to candidates that, beginning immediately, they should stick to the old limits.

Mike Liburdi, who represents the GOP legislative leaders, said this isn’t the last word. He is weighing an immediate appeal to the state Supreme Court.

Tuesday’s decision is a sharp rebuff for House Speaker Andy Tobin and Senate President Andy Biggs, who argued lawmakers are free to alter — or in some cases, abolish — limits on what candidates can take and donors can give.

The new law allowed legislative candidates to take up to $4,000 for their campaigns from any one source. The old limit was $440. The ruling also restores a $14,688 limit on how much candidates can take from all PACs for any election, and a $6,390 lid on the amount any one individual or PAC can give to all candidates in any year. The legislation had abolished both caps.

The ruling came just hours after Kanefield told the court the optional public campaign funding system approved by voters in 1998 included limits on how much candidates who choose to run with private dollars could accept, and the Arizona Constitution prohibits legislators from tinkering with anything that has been voter enacted without a three-fourths vote, which the new law did not get.

Liburdi, in attempting to keep the higher caps in place, told the judges they should consider a larger issue: When are campaign finance limits unconstitutionally too low?

He argued that legislators really had no choice but to raise the limits. He said the old caps on how much candidates could take from any one source likely violated their constitutional right to raise sufficient funds to wage effective campaigns.

Bennett said he was not surprised by the ruling. “I personally felt that the plaintiffs (who challenged the law) had some very good points,’’ he said.

Bennett said he believes lawmakers could not legally increase contribution limits for privately financed candidates, given constitutional prohibition on altering voter-approved measures. He said the only way that might have been acceptable is if legislators had also increased the amounts given to those running with public dollars, something they refused to do.