Transit riders could be in store for big service disruptions as the Massachusetts Bay Transportation Authority prepares to boost maintenance spending in the coming years.

In his first public remarks since taking the reins, new MBTA general manager Steve Poftak said on Monday he is focusing heavily on the five-year, $8 billion spending plan that the Baker administration previously charted. While the agency is on track to meet its $1 billion spending goal this year, boosting spending even more in the next few years will be a major effort, he said. So, too, will be meeting a goal to fully repair the transit system’s aging infrastructure by 2032.

Poftak said he is launching an agency-wide review to ensure the T is equipped to issue and manage the dozens of contracts that officials promise will improve the morning commute.

“I really view the delivery of this capital program as an existential necessity for the MBTA, in terms of improving reliability, maintaining and modernizing the system, and as proof to our customers that we can truly deliver on the promise of better performance,” he said.

But reaching that promised land may first require frustrating trips on shuttle buses for riders, who have already seen commuter rail lines closed on certain weekends for the installation of collision-avoidance technology, stations closed for years at a time for renovations, and subway branches partially shuttered on nights or weekends for track work.

The problem, said Brian Shortsleeve, a former T general manager and now a member of its board of directors, is that there are only a few short hours between the end of service one day and the start of service the next. If the T is going to make major repairs in relatively short order, he said, those tracks may need to stay clear for longer periods.

“If it means we’ve got to do big shutdowns, and maybe the organization needs some tough love on that, I think we should do it,” Shortsleeve said at a board meeting on Monday.

Officials on Monday spoke in general terms, not naming any specific disruptions that may surface in the future. Already, the project to fully replace the Red and Orange line signal systems is expected to take trains out of service for several weekends in the coming years. Even then, that work is still expected to take until 2022.

Jeff Gonneville, the T’s deputy general manager, said part of the review Poftak ordered will focus on these types of service disruptions, and how to improve alternative services for riders when they are happening.

During Governor Charlie Baker’s reelection campaign, his Democratic challenger, Jay Gonzalez, said the T’s 15-year plan to fully repair the system would take far too long. But administration officials said speeding up the process would require much more significant service disruptions.

Transportation Secretary Stephanie Pollack on Monday said she was open to bigger shutdowns. But, she said, officials should plan these shutdowns to incorporate several projects at once.

Pollack said her own commute on the D branch of the Green Line has been disrupted some nights by track and signal work.

“That’s fine except for if, two years from now, we have to go back to the same geography and do a diversion for a different project because we didn’t plan far enough ahead to find all the projects that affected the same line or the same set of stations,” she said. “That’s really asking a lot of the customers. . . . We have to at least be able to assure them that we’ve done it in a strategic way.”

These discussions are surfacing at the MBTA a week after a major change in plans in New York City, which was just months away from fully closing a major rail line between Brooklyn and Manhattan for more than a year for repair work related to Hurricane Sandy. But Governor Andrew Cuomo recently surprised the city, announcing that plan had been suspended and instead replaced with a new construction process that would not require as severe of a service shutdown.