Developers of the proposed $500-million Smoot Bay complex beside the Beltway's Woodrow Wilson Bridge have won Maryland State Highway Department approval for the first stage of the development, which will include a marina, hotels, offices and residential areas. But they have just begun the fight for county approval of the extensive rezonings they need for the project.

Public hearings on rezoning the vacant woodland and Potomac River shoreline, presently zoned for rural residential use, began in Upper Marlboro last week and will be continued Dec. 17. A third day of hearings may be necessary since the developer has just begun detailed explanations of the project and local citizens have yet to be heard.

State highway approval was granted recently in exchange for promises by developer James Burch to pay for improvements to the Indian Head Highway (Rte. 210) and Oxon Hill Road interchange at the Beltway.

Prince George's County planners, while urging approval of most of the rezoning with many conditions, have strongly opposed any construction until the planned $25 million to $30 million extension of I-295 is completed to Indian Head Highway. That may not occur until 1987 and federal-state funding for it is still in doubt.