NIAGARA FALLS — A ninth-floor observation deck in One Niagara on Rainbow Boulevard is open to the public after a judge’s ruling allowed the building’s manager to sidestep approval from the city to open the top floor.

Supreme Court Justice Richard C. Kloch Sr. on Thursday issued an order to allow the building’s ninth floor to open while its manager, Frank Parlato Jr., seeks new site plan approval for the building and a certificate of occupancy for the ninth floor.

Parlato, who is also a co-owner of the mostly glass-encased building, opened the ninth floor as a free indoor observation deck Friday with 10 benches, four viewfinders and a small souvenir shop.

The upper rapids in the Niagara River and a sliver of the falls can be seen from the building’s top floor, as well as bird’s-eye views of Niagara Falls State Park and downtown Niagara Falls.

“We honestly didn’t know if we’d be able to open or not,” Parlato said Tuesday. “It took me longer than I thought, but I didn’t calculate Niagara Falls politics very well.”

Parlato last month sued the city, asking the judge to require the city to issue permits and a certificate of occupancy for the ninth floor.

Kloch on Thursday issued an order allowing Parlato to use the ninth floor while a new application is submitted to the city to amend the building’s site plan “within a reasonable period,” said Parlato’s attorney, Paul Grenga.

Grenga contends that the city had “arbitrarily and capriciously” withheld approvals for the building.

The city’s Planning Department had deemed Parlato’s application for a new site plan incomplete. It had not yet been reviewed by the city’s Planning Board.

Craig H. Johnson, the city’s corporation counsel, said the city had not yet received a written order from Kloch.

“As soon as that order is forthcoming, the city will review its options, including an appeal,” Johnson said.

The city in June 2008 declared the building’s site plan approval “null and void” because the building did not comply with the plan. Johnson notified an attorney for Parlato in January that the city would not issue any new permits for the building until the site plan application and approval process is complete.

The building’s certificate of occupancy from the city is only for its first floor.

Parlato said he has plans to add interpretive signs and information explaining the region’s geography to the ninth floor within a few weeks.

“Maybe this isn’t much, but it’s a start,” Parlato said. “It’s free.”

Parlato estimated that hundreds of people took the elevators to the building’s top floor during the holiday weekend.

One Niagara, once an office building for Occidental Chemical, was the site of a failed underground aquarium before Parlato took over the building. He filled in a 40-foot hole on the property and opened a paid parking lot and welcome center with food and souvenir vendors.

In recent years, One Niagara has operated under a cloud of lawsuits over control of its operations and city building regulations.

Tuesday afternoon, about a dozen tourists milled around the top floor. The concrete floor has been painted a light yellow, windows have been scrubbed and an air-conditioning unit has been upgraded.

Benches and viewfinders look out across the Niagara River and the Niagara Gorge.

One upstate family leaving the building on the way to a camping trip seemed less than impressed after taking the elevator to the top floor.

“Not much to see,” said Jason Nasto of Rome. “We go mostly to the Canadian side, and it’s a lot nicer.”