The Hughes administration, attempting to forge a partnership with the federal government to pay for the dredging of Baltimore Harbor, announced today a partial financing plan for the $360 million project that could hinge on the sale of the World Trade Center, the choicest piece of state-owned real estate on the harbor.

Gov. Harry Hughes, reiterating his belief that Maryland and the U.S. government should split evenly the cost of deepening the Baltimore harbor channel, also proposed spending state transportation funds for what he described as the "long-delayed" dredging project.

"The state is in a position to proceed with this project" without an immediate tax increase to pay for it, Hughes said in a letter to legislative leaders.

Hughes and other state officials hope the proposal, which is more detailed than past plans, will signal to federal authorities that the state is committed to harbor dredging. Indeed, the package came two days before the governor was to meet in Washington with members of Maryland's congressional delegation to press for passage of federal dredging funds this year. Last December, Congress approved a water projects bill that contained federal funds for port dredging, but President Reagan vetoed the measure.

Two members of the congressional delegation said today Hughes' proposal could be key in ensuring federal support for dredging. Rep. Barbara Mikulski, a Democrat whose district includes part of the port, said Hughes was "doing his part by getting the state's share ready."

And freshman Rep. Helen D. Bentley, a Baltimore County Republican who was elected in 1984 after pledging to work to improve the harbor economy, said she was "glad to see the state moving forward" with a plan to fund its share of the project.

Bentley and Mikulski said they expect Congress to appropriate dredging funds but stressed that such a spending plan may allow for only incremental deepening of the harbor channel. Mikulski is a sponsor of legislation calling for the federal government to deepen the port's 42-foot channel to 45 feet, after which the state would pay for half the cost of dredging to 50 feet; a somewhat different proposal is pending in the Senate.

State officials and labor and business leaders have backed the dredging for years, saying the area economy will stagnate if larger ships cannot dock in Baltimore.

Business leaders estimate that the port generates more than $2 billion annually for harbor industries and personal income for Maryland residents.

A key provision in the state's plan to come up with its $180 million share for dredging is the optional sale of the World Trade Center, a 30-story building on the harbor's edge that in the 1970s helped spur the multimillion-dollar development of the city's Inner Harbor of offices and shops.

By selling the trade center, the state could raise two to three times the $22 million it cost to construct the building in 1977, officials said. The center is operated by the Maryland Port Administration and is fully occupied, mostly by businesses related to maritime trades.

State Transportation Secretary William K. Hellmann, who drafted the financing plan with House Speaker Benjamin L. Cardin and other legislative leaders, stressed that the trade center may not be sold if the state can raise its share through the sale of transportation bonds or general transit revenues. But Hellmann added that state officials were "getting ourselves in position to move quickly to sell the center if that is the way to proceed."

Any sale would not proceed "until we reach an agreement with the federal government," Hellmann said.