A city councilman is calling for an "immediate and thorough" audit of the city's finance department after The Sun reported on persistent tax bill errors that have caused the city to miss out on revenue.

Councilman Carl Stokes, chairman of the council's taxation committee, plans to introduce two resolutions Monday about the issue. The first resolution calls for the audit, which Stokes says is necessary to "determine exactly what errors have been made in administering the city's property tax programs and how much these errors are costing the city."

Comptroller Joan Pratt, whose office oversees city audits, could not immediately be reached for comment.

Stokes' second proposal calls for the finance department, which reports to Mayor Stephanie Rawlings-Blake, to consider privatizing tax calculations and collections to put an end to the "chronic and costly tax errors plaguing Baltimore." 

"It is one level of incompetence to continue to have so many errors, but it is another level of indifference not to address them time and again and not to allow a true and full accounting to the citizens and taxpayers of Baltimore City," Stokes said.

Rawlings-Blake, who recently called the persistence of tax bill errors is a "serious problem," planned a news conference for Monday to address the issue.

Her spokesman, Kevin Harris, said Rawlings-Blake plans to announce "new reforms finance has put in place to help reduce errors, particularly those related to human error."

City finance officials say major changes are being made to the tax credit process that will allow the city to automate the calculation of credits and to track credits over a period of years. Harris has said the city expects to implement upgrades in the coming weeks.

The Sun reported last month that the city has undercharged the owners of three commercial properties by more than $700,000 in recent years because of errors by city and state officials in calculating tax breaks. Among them is One Charles Center, a 23-story downtown office tower owned by Orioles majority owner Peter G. Angelos.

In some cases, the erroneous tax bills were later corrected by the city. 

The errors in the Enterprise Zone tax break program come amid other reported problems in city tax collections, including bills for homeowners and historic properties. In recent years the city failed to collect more than $2 million because of errors in other tax programs, The Sun has found.

This year the city took over the job of computing Enterprise Zone and other credits from the state after city officials grew frustrated with what they deemed too many calculation mistakes by the state — errors the city failed to catch at the time they were made.

Luke.Broadwater@baltsun.com

Twitter.com/lukebroadwater