Saying "I have the strongest record of tax reduction of anybody in this city," Democratic mayoral nominee John Street yesterday assailed Republican foe Sam Katz for promising to reduce the city wage tax to 4 percent without so far offering a plan to do it.

Calling Katz's general proposal "frightening" and "mind-boggling," Street repeatedly intoned, "Where is the plan?" over the sound of passing traffic as he stood outside of a fire station at Cottman and Loretto avenues in the Northeast.

But Bob Barnett, Katz's campaign director, said the Katz plan was in the works and would be released soon.

"All that Sam has said is that he intends to reduce the wage tax for city residents to 4 percent by the end of his first term," Barnett said.

Mayor Rendell's current five-year plan calls for reducing that rate from its current 4.6135 percent to 4.4615 percent by 2004.

Among those endorsing Street were U.S. Rep. Bob Borski, D-Pa., and a gaggle of union leaders including AFL-CIO leader Joseph Rauscher who said Street has solid labor backing.

Also endorsing Street was City Controller Jonathan Saidel who backed Marty Weinberg in the Democratic primary.

During the primary it was Weinberg who proposed lowering the wage-tax rate to 4 percent, earning him scorn from Street, Rendell and others for a so-called "irresponsible" tax proposal.

But not Saidel. In 1994 Saidel himself proposed a 10-year tax cut process that would have reduced the city resident wage-tax rate to 2.96 percent by 2005. So, what's changed?

"It depends on the hypotheticals," Saidel said. "The world has changed from May to October."

Street said a cut to 4 percent would result in a loss of more than $500 million over four years.

Later, Rendell came to his political sidekick's aid. "I say this with a great deal of hesitancy because I have a high regard for Sam, but he either doesn't understand or he's made a promise to achieve votes," Rendell said.

Barnett had a quick response. "It's irresponsible of the mayor to criticize a plan before it's been presented and he's had a chance to read it, and he'd be irritated if someone did that to him."

Street contends that the $500 million would have to come out of basic city services, from fire and police to recreation and libraries.

But Street's $500 million figure assumes that Katz would reduce taxes in one fell swoop in his first year and hold it at that level for four years - an unlikely strategy. "We don't know what he'll do so we've had to guess," said one Street staffer.

Rendell and City Council have reduced taxes in small increments since 1995, from 4.96 percent to 4.61 percent.

The taxation debate made for one of the liveliest exchanges of the campaign last night at the Philadelphia Free Library in a forum sponsored by the Friends of the Philadelphia Parks.

Katz pledged that he would start a large-scale capital campaign to increase funding for the parks, and that his wife, Connie, had volunteered to chair it and enlist the aid of school children in seeking funds. Said Katz: "We can think outside of the box."

Staff writer William Bunch contributed to this report.