The cost of commuting by bus or train in New York City would skyrocket next year under a plan unveiled Thursday by the nation's largest public transit system.

The Metropolitan Transportation Authority said it needs to raise fare revenue by 23 percent by June in order to plug a yawning budget gap worsened by the global financial crisis.

The details of just which fares will rise, and by how much, are still being worked out, but if applied across the board that could raise the cost of a single bus or subway ride to nearly $2.50. A monthly pass would cost nearly $100.

Adding insult to injury, the authority simultaneously proposed service cuts that include the elimination of bus and subway lines in areas where there is either low ridership, or a duplication of services.

While none of the changes would cut off neighborhoods entirely, they will mean longer travel times, more waiting around on the platform, and stuffing more people into subways that are already overcrowded.

MTA Executive Director Elliot Sander said he anticipates "an emotional reaction" from New Yorkers upset with the changes, but said the authority has no choice. It is required by law to balance its budget.

If the system doesn't take action, it would face an estimated $1.4 billion deficit in its operating budget next year and a $3 billion deficit by 2012, Sander said.

"None of us wants to see a return to the kind of transit system that defined New York in the 1970s," he said.

The cuts and fare hikes still need to be approved by the MTA's board before they take effect. That vote is expected in December, following a round of public hearings.

There is also a chance that a commission appointed by New York's governor to examine the MTA's finances and structure could make alternative recommendations next month.

Some of the specific changes proposed by the MTA during a board meeting Thursday include a hike in the express bus fare from $5 to $7.50, as well as a major increase in fares for paratransit services.

On the subway system, the Z train, which links parts of Brooklyn and Queens to downtown Manhattan, would disappear and have its stops taken over by the J train, which already covers the same route. The W train, which runs from Manhattan to Queens, would also vanish and have its stops taken over by other trains.