A public plaza planned atop an underground parking garage for a new 24-story office building downtown will cost taxpayers more than expected.

But Salt Lake redevelopment officials and the developer of the garage and office complex are downplaying a dispute over $5.5 million in costs associated with the project at 201 S. Main, a part of Block 57.And the city's Redevelopment Agency Board voted Thursday evening to pay $2.45 million of the disputed costs as a good-faith measure to keep the project going and to reassure anxious contractors.

"When they read in the paper and hear on the news that there's a dispute, contractors say `you mean there's a dispute and we're not going to get paid?' " said Kem Gardner, president of Boyer Co. "The word dispute was unfortunate because it said to the press there were overruns."

However, the project is costing more than RDA board members originally thought. They approved $9 million for the garage and plaza in 1989. The agency agreed Thursday to pay $4.9 million more than that, including the $2.45 million in disputed costs.

The dispute stems from the wording of the contract between the redevelopment agency and Boyer. The agency was to pay for costs associated with the plaza, while Boyer was to pay for costs associated with the garage.

Since the two projects are connected, both sides are having difficulty deciding what part of the structure is necessary to shore the plaza and what parts are needed solely for the garage.

In addition, the weight of the plaza and unanticipated soil conditions have caused workers to use pile-driven footings instead of standard ones.

Redevelopment director Alice Larkin Steiner said the $2.45 million the agency paid Thursday is "a fairly safe assumption of what we owe." She told board members it was important to pay the money now and that the project had not yet exceeded its budget.

"Any time you have a construction job, it's very important to keep money flowing to that job," she said.

Meanwhile, Boyer officials said the seven-story Utah Savings and Trust Bank building, listed on the National Register of Historic Places, will be demolished Saturday. The building, completed in 1907, stands adjacent to the new office tower and garage.

The redevelopment agency bought the structure for $2.5 million in 1986 and renovated it. However, it announced earlier this year that attempts to sell the building had failed. Critics, however, claim the agency never seriously tried to market the building.