A new downtown arena for the Utah Jazz could cost $67 million, and some members of a committee responsible for researching the costs of the proposed project say that figure may be too low.

The estimated arena price tag was just part of a $158 million wish list of projects released Thursday by the committee - including an estimated $62 million for upgraded and expanded convention facilities, $20 million for a science center and $7 million for a performing arts center.Although Salt Lake County commissioners have pledged they will not raise taxes to build a new arena, committee members were clearly concerned about the public perception of, and reaction to, their cost estimates, released just two days after voters rejected three tax-limiting initiatives.

"How are we going to sell this to the public?" asked concert promoter J.C. McNeil, a committee member.

The committee, working under the direction of a task force appointed by commissioners to look at options for a new arena, was asked only to explore costs of the proposed projects. A separate finance committee next week will take up the task of determining how the projects are to be funded.

As proposed, the arena would seat 18,500 for basketball games. To accommodate ice hockey, one tier of seats would be retracted, exposing a larger floor area and reducing seating to 12,500.

The $67 million estimate includes $45 million in direct construction costs, $9 million for a parking terrace and another $9 million to acquire land. The committee had already recommended building the arena on Block 79, between South Temple, First South, and Third and Fourth West streets, directly south of the Triad Center.

But some committee members said the construction cost estimates may be optimistic, and actual costs could run several million dollars higher. The committee must walk a fine line with its cost estimates, said chairman Dave Richards.

"We want to be as realistic as possible, but it's a two-edged sword," Richards said. "If the numbers are too high, we may have trouble from the start making it financially feasible. If they're too low, we have to go back and rework everything."

The proposed convention facilities - a new banquet hall, 100 new meeting rooms and 150,000 square feet of exhibit space - and a remodeling of existing facilities is needed to make the city competitive in that market, said Thayne Robson, vice chairman of the county's task force. The city recently lost two large conventions to Denver's new convention facilities, he said.

A separate science center task force has said that facility - composed of the Hansen Planetarium, a large-screen theater and a science museum - can be funded entirely by private corporate donations. However, the costs committee's report is the first attempt to put a price tag on that project.

Committee members will arrange the projects according to priority and may break the individual proposals into prioritized phases of development before turning their report over to the finance committee.

"Some of these things may never happen," said committee member Frank Ferguson, an architect.

"We have to get the first phase taken care of and then move on."