PORTSMOUTH — The Sarah Mildred Long Bridge remained closed after malfunctioning Sunday morning, it won't be fixed on Tuesday, and because a replacement bridge is being built, it's possible it may never reopen, said New Hampshire Department of Transportation spokesman Bill Boynton.

"It's definitely not opening Tuesday," Boynton said Monday afternoon.

"Ultimately it has to be decided whether it is worth the investment to keep it open 10 more weeks, especially if it takes three or four weeks just to fix it."

The 76-year-old bridge, over which 14,000 vehicles pass daily between Portsmouth and Kittery, Maine along the Route 1 Bypass, malfunctioned Sunday at about 11 a.m., Boynton said. At that time the bridge's lift span seized in the closed position which meant vehicles could pass over it, but large boats couldn't pass under it.

At about 1:15 a.m. on Monday, Boynton said, the lift span was raised because federal law mandates that river traffic take precedence over motor vehicles. Since that time, he said, the bridge span has been stuck in the up position, meaning no motor vehicles can pass over it.

Boynton said the cause of the malfunction is attributed to a wheel on a southwest corner tower, on the New Hampshire side, that carries cables for lifting the span. He said experts from Maine and New Hampshire's transportation departments are consulting, as are experts from the Cianbro construction company, which is in the process of constructing a replacement bridge adjacent to the current bridge.

"All indications are it's not an easy or quick fix," Boynton said.

Boynton said the consultants are studying the seriousness of the problem and whether it can be repaired for a reasonable cost. The bridge is scheduled to be closed permanently in early November, so that is a factor under serious consideration, he said.

"There will be discussion about whether it makes sense to repair," Boynton said. "The good news is that it is up because there was a large ship waiting to get out."

Boynton said the bridge will remain closed, with the lift in the upright position. In the meantime, he said, drivers are encouraged to use the Interstate 95 Piscataqua River Bridge, known as the high-level bridge. That span has the capacity to carry more traffic than the Memorial Bridge located near the Portsmouth downtown, he said.

The new Sarah Long Bridge is scheduled to open Sept. 1, 2017. The project is scheduled to be fully complete by June 1, 2018.

— Howard Altschiller contributed to this story.