Anne Arundel County election officials confirmed yesterday that the taxpayer group trying to get a property tax limitation initiative on the November ballot had obtained the necessary signatures, but the county attorney said that they plan this week to challenge the constitutionality of that initiative in court. "It is dead, cold unconstitutional," said Steven R. Beard, county solicitor.

The initiative would roll back property tax revenue to 1989 levels and then limit the amount of property tax revenue collected each year.

The head of the group that mounted the petition drive, part of a wave of tax rebellion that has struck in Baltimore and Montgomery counties, said he was incensed by the county's efforts to keep the initiative from coming to a vote.

"This is some sort of sneaky, underhanded way of keeping this off the ballot. If the people agree with the county, let the people prove that in November," said Robert C. Schaeffer, president of Anne Arundel Taxpayers for Responsive Government. "They are subverting the will of the people."

Solicitor Beard said county officials, who strongly oppose the initiative, "would like to subject it to a legal challenge." He refused to specify the grounds on which he will sue.

"There is no means set up for an automatic review, so we are going to file suit on behalf of an individual taxpayer," Beard said. "We will make the claim that the initiative is inconsistent with the state Constitution and state law."

Leaders of several civic groups applauded the county government's planned move and said they had asked County Executive James Lighthizer to review the legality of the taxpayers' initiative.

"I'm no lawyer, but I don't believe it is legal for them to take away something that I have now," said Ray Smallwood, president of the Federation of West County Civic Associations.

"It's like somebody saying, 'I'm not going to get my trash picked up because I don't want to pay for it,' " said Smallwood, whose group represents 30 civic and condominium associations. "That's fine for them, but I don't want that small number of people taking away my trash pickup."

County officials have said that the provision would cost local government $30 million to $45 million, the equivalent of 7.3 percent of this year's budget.

Barbara Fisher, deputy administrator of the county election office, said officials validated 11,817 of the 20,000 signatures turned in by the group after its 3 1/2-month petition drive. The county charter requires 10,000 signatures.