The Navy plans to cancel nearly all repairs at bases and maintenance on ships and planes for this fiscal year unless Congress agrees on a new budget.

The Navy faces a $4.6 billion shortfall for the year in its operation and maintenance account.

Most piers, runways, buildings and other facilities will not be fixed or modernized through September and bases will receive less money for upkeep, Adm. Jonathan W. Greenert, the chief of naval operations, wrote in an email to all senior officers and executives on Thursday to answer questions about the impact of the fiscal situation.

Employees who were hired by the Navy on a temporary basis will be terminated and a civilian hiring freeze is in effect, which reduces the workforce by more than 3,000 people.

Greenert did not specifically address his plans to maintain submarines. A Navy official said it was unclear what effect the cost-saving measures will have on submarine maintenance, but it is something the Navy is evaluating.

Robert Hamilton, spokesman for Electric Boat, said Thursday the shipyard has not been notified of any cancellations at this point. Christopher Zendan, spokesman for the Naval Submarine Base in Groton, said he could not immediately say what the impact on the base would be.

Thirty surface ships will not be sent to the private shipyards for maintenance between April and September and all aircraft depot maintenance during that same period will be canceled, which affects about 250 planes.

The government is operating on a continuing resolution that funds spending at last year's levels and limits the Navy's ability to transfer funds between accounts to cover shortfalls. The continuing resolution expires March 27, and Congress could extend it for the rest of the fiscal year.

The maintenance account will need to be cut by another $4 billion if Congress does not act before March to avoid automatic spending cuts known as sequestration, Greenert said.

If sequestration does occur, the Navy would reduce operations in the Middle East and Pacific and stop certain training and exercises for assets that aren't deployed, which ultimately will prevent Carrier Strike Groups and Amphibious Readiness Groups from deploying, he said. The Navy would likely not have trained replacements for deployed units in fiscal year 2014, he added.

Greenert said reductions have to be made - starting now - so the Navy can pay for ongoing deployments and other activities critical to the mission. The budgets for information technology and travel were also cut.

"These steps come at a price," Greenert wrote. "Much like putting off an oil change because you can't afford the $20 service, we save in the short-term but shorten the car's life and add to the backlog of work for later."

The reductions are reversible, Greenert said, and will continue until a spending bill is passed or Congress allows the Navy to reprogram money.