A dissident member of the National Maritime Union has filed a lawsuit in federal court seeking to block his union's plan to merge with District 1 of the Marine Engineers Beneficial Association.

MEBA-1 members are currently voting on the plan; the unions plan to implement the merger on April 1.The lawsuit was filed Friday in the U.S. District Court for the Southern District of New York by Albert S. Jackson Jr., a Wilmington, Del., resident who unsuccessfully ran for secretary/treasurer of the NMU in 1983, an election he says was seriously tainted.

Mr. Jackson's attorney, Arthur L. Fox II, has also requested the Department of Labor to investigate the merger under Title IV of the Labor-Management Reporting and Disclosure Act.

Mr. Fox says an NMU referendum on the merger last year was flawed and NMU members were unable to play a meaningful, democratic role in the governance of their union.

He wants the court to declare the referendum illegal and enjoin the NMU

from implementing the proposed merger unless or until it should conduct a lawful referendum.

If a new merger referendum is conducted, Mr. Jackson wants an opportunity for opponents of the merger referendum to air their opinions.

Copies of the NMU-MEBA-1 merger agreement and proposed constitution that were mailed to NMU members were no more comprehensible to the average NMU member than a registration statement or indenture agreement would be to the

average shareholder; nor was it any more likely that the NMU member would read this document than the average New Yorker would read the Manhattan telephone directory, Mr. Jackson's lawsuit says.

Mr. Jackson, who says he supports a merger of the NMU with another maritime union, says the implications of the merger - both negative and positive - weren't explained to NMU members. Mr. Jackson says the current merger agreement will perpetuate the current leadership of the NMU, a group he opposes.

In his letter to the Department of Labor, Mr. Fox says that nine years will pass after the 1983 elections before the NMU membership will again be allowed to vote for their officers.

Mr. Fox says an investigation by the U.S. Senate Permanent Subcommittee on Investigations found serious flaws in the 1983 NMU election.

That committee found that staff members of the Department of Labor's Office of Labor-Management Standards and Office of the Solicitor recommended that the election be overturned and held again. But the Department of Labor decided not to institute proceedings to overturn the election results.

Mr. Jackson's attorneys said last week they were preparing a motion for a preliminary injunction barring the merger that they will present to Judge Richard J. Daronco, the judge assigned to the case.

NMU officials and attorneys were not available for comment Friday. When Mr. Jackson unsuccessfully tried to have the merger ballot thrown out through internal procedures, union officials noted the union members voted 4,788 to 414 in favor of the merger.