"The national economic meltdown might have justified austerity measures like forced unpaid leave, or furloughs," the letter said. "But with the economy rebounding, it is difficult today to argue that those who fix our potholes, salt and shovel our streets, and process our business licenses deserve less than they currently receive."
The city's current five-year plan does not call for furloughs.
But the administration has contended that if another major economic downturn occurred, the ability to furlough workers for short, specified periods would permit better, more flexible management of the city budget and be more humane to city workers than layoffs.
Leaders of both AFSCME councils have condemned the furlough language, saying that the administration wouldn't want the authority if it didn't intend to use it - thereby depriving workers of up to three weeks' pay.
The two AFSCME bargaining units, representing about 15,000 city workers, have been working under the terms of expired contracts since mid-2009, without raises in pay or benefits.
City Council's letter was initially drafted by Council President Darrell L. Clarke and circulated last week to other Council members.
"I appreciate Council's continued interest," Nutter told reporters Monday. "It's a top priority for me. But it's not just about signing a contract, it's can we afford that contract."
The mayor declined to discuss the particulars of the administration's furlough demand.
"I'm not going to parse through all the different elements of what we've put forward," Nutter said. ". . . I understand that's an area of particular concern to the union leadership."
Tension over the stalled negotiations has been increasing as the administration prepares its budget proposal for the year starting July 1.
The mayor is expected to send budget documents to Council in early March, and by tradition, he would deliver a budget message in person.
But after a raucous demonstration by union members last March, forcing Nutter to suspend his speech and deliver it two hours later to his own aides and cabinet members, the mayor's office has not yet confirmed a date this year for his budget presentation.