Views from Buffalo’s tallest building might soon be more accessible to more people.

An observation deck and banquet facility are under consideration for the top floors of the HSBC tower, a top official with the building’s owner said Tuesday.

“We might be able to actually put some kind of an outdoor area on the roof of the building, but that would take an awful lot of engineering, making sure that’s done right,” said Stephen Fitzmaurice, chief operating officer of Seneca One Realty LLC.

Uses for the tower are on the mind of many in Buffalo beyond Seneca One. The building’s projected vacancy rate of 92 percent, caused in part by the departure of two of the major tenants next year, is expected to impact the regional real estate market.

In an effort to attract tenants from outside the area and create uses for the building that don’t involve moving office workers from one downtown building to another, national experts will come to Buffalo early next year to examine a mixed-use plan for One HSBC Center.

“When was the last time someone leased a condominium, or bought a condominium, on the 30th floor or the 36th floor of a building [in Buffalo]? That doesn’t exist right now,” Fitzmaurice said. “We can do a lot of things we haven’t been able to do.”

The building is 40 stories, but the top two floors are used for mechanical equipment. The 38th floor would perhaps be used for a banquet facility and a restaurant, and the 37th floor could house an observation deck unlike anything else in the city, Fitzmaurice said.

City Hall’s observation deck is on the 28th floor, but it’s smaller than what the tower could offer.

Seneca One is also looking at the possibility of bringing in back-office operations for law firms in more expensive cities as a way to fill floors that will continue to be used for office space.

HSBC announced earlier this month that it is moving its operations elsewhere, and in late 2013, law firm Phillips Lytle is moving into One Canalside, at the site of the former Donovan State Office Building. The Canadian Consulate has also moved out of the tower.

The Buffalo Urban Development Corp., an economic development agency, on Tuesday approved spending $10,000 from its Regionally Significant Project fund to help bring in a panel of architecture, real estate, banking and urban planning experts through the Urban Land Institute for three days to review proposed plans for the building and to offer input.

The panel will weigh in on how the building should be used; it will not pursue major tenants, said David A. Stebbins, vice president of the urban development corporation.

Seneca One is also paying $10,000 to bring the institute in, and the urban development group has submitted a grant application for $20,000 to National Grid.

To assist in their analysis, the experts will receive comprehensive data about Buffalo in advance of their visit, Fitzmaurice said.

The institute’s panels also have been used in planning for the redevelopment of the former Millard Fillmore Hospital complex and the Rainbow Centre-Culinary Institute project in Niagara Falls.