Oakland's police force will keep shrinking, with voters having rejected two out of three revenue-raising measures on the ballot this week, City Administrator Dan Lindheim said Thursday.

The force now has 673 officers, but Lindheim said the city's 2010-11 budget and money the city will receive under Measure BB - the initiative that voters did approve Tuesday - provide enough for just 637 officers through June.

Oakland laid off 80 officers in July to help balance its budget, but the additional reductions will come through attrition, Lindheim said.

"We probably won't have to do additional layoffs," the city administrator said at a news conference with City Council President Jane Brunner.

Former state Sen. Don Perata, who has a significant lead in the mayor's race with ranked-choice votes yet to be distributed, has vowed to rehire the 80 laid-off officers if he is elected.

But Brunner, who endorsed Perata, questioned whether the city will have the money to do that.

"Somebody is going to have to be very creative," Brunner said.

Although they approved Measure BB, enabling the city to keep collecting revenue from a $90-a-year parcel tax that pays for police services, voters rejected two additional revenue-raising measures Tuesday. One, Measure X, would have imposed a $360-a-year parcel tax to provide more money to police, and the other would have taxed telephone lines.

The passage of Measure BB gives the city $20 million a year. But the terms of the original 2004 parcel tax mean the Police Department will have to pull 57 officers and six sergeants from various units and assign them to community policing positions known as problem-solving officers.

Officers will be removed from specialized units to fill those spots, including investigations, traffic and street-level narcotics teams, said Officer Jeff Thomason, a department spokesman.

Whether the Police Department will be able to avoid further reductions next fiscal year is unclear.

Originally, the city had projected a $50 million deficit for the fiscal year beginning July 1. But Lindheim said Thursday that the figure would probably be $10 million, thanks to cuts the City Council made this year and one-time infusions of revenue.

Those cuts include the officers laid off and the positions the Police Department will lose until the force reaches 637 officers.

The police union president said it was premature for Lindheim to discuss police staffing because the new mayor would determine those priorities.

"The leadership is out of this city in a month," said Sgt. Dom Arotzarena, president of the Oakland Police Officers Association, which endorsed Perata. "Come on."

Lindheim serves at the discretion of the mayor. He has worked under the outgoing incumbent, Ron Dellums, since the mayor's days in Congress.

The police force "is hardly functioning now," Arotzarena said. "To go less, it's not going to function. Period."