A plan to add four new police officers to the city’s force overcame last-minute objections as Lawrence city commissioners approved a 2012 budget and a property tax increase Tuesday evening.

City commissioners narrowly rejected a proposal by City Commissioner Bob Schumm that would have reduced a planned expansion of the police force. Schumm lobbied for the proposal in order to reduce the property tax mill levy needed to fund the 2012 budget.

But commissioners balked.

“As much as I’m tempted to keep the mill levy flat, I think this is an occasion where we are pretty far behind already in this area,” said Mayor Aron Cromwell.

Cromwell and City Commissioners Hugh Carter and Mike Dever agreed to move ahead with the four new police officer positions, plus funding for an existing detective position that currently is funded by an expiring federal grant. Schumm and City Commissioner Mike Amyx voted to move ahead with just two new police officer positions, plus the detective.

The action means the city’s property tax rate will increase by 1.88 mills in 2012. The bulk of the increase comes from a voter-approved expansion of the Lawrence Public Library that will add 1.7 mills to the budget. The remaining 0.18 mill will fund the police officer positions. Schumm’s proposal would have allowed the mill levy to rise only by the 1.7 mills set aside for the library.

The vote brought to an end a series of proposals that started flying around City Hall as the 2012 budget entered the homestretch. Schumm made his proposal to reduce the size of the police expansion on Monday. Carter, before Tuesday’s meeting, countered with a proposal to lay off three employees in the city’s planning and development services department, if city commissioners were intent on cutting 0.18 mill from the city budget, which amounts to about $4 a year in taxes on a $200,000 home. Carter said it was critical for the full police expansion to move forward.

City commissioners ended up having little appetite to discuss layoffs in the planning and development services department. Both Cromwell and Dever expressed their support for the full police expansion before Carter could ask for a vote on the layoffs.

“We have a new police chief, and he has stated that his professional opinion is that we need more police officers,” Dever said. “It is difficult to raise the mill levy, but we have to remain committed to making Lawrence a better community.”

In total, the 1.88 mill levy increase will amount to an extra $43.24 per year in taxes on a $200,000 home.

Commissioners also approved several other fee and rate increases as part of the 2012 budget. They include:

• A 2 percent increase in water rates and a 2 percent increase in sewer rates.

• A 2.7 percent increase, or about 40 cents per month, for residential trash service.

• A $7 increase in the city’s Municipal Court fee. The new fee, which represents the court costs that are added onto a ticket, will total $60.

Commissioners gave preliminary approval to an increase in the city’s system development charges, which are one-time fees charged to new construction that hooks onto the city’s sewer and water systems. The increase is set to be $340, or an 11 percent hike. Members of the city’s building and real estate industry have asked for the increase to be delayed a year in order to give the industry a chance to recover from the economic downturn.

A majority of commissioners said they were leaning toward approving the increase but said they wanted more information from city staff about what the impacts would be of delaying the increase for a year.

Technically, all matters related to the city budget must receive one more vote before becoming final. Commissioners will approve the budget on second reading at their meeting next week.