Westway, a multibillion-dollar highway and development project, cleared a major hurdle today as the head of the regional office of the Army Corps of Engineers recommended approval of a crucial landfill permit.

However, three federal agencies -- the Environmental Protection Agency, the Interior Department's Fish and Wildlife Service and the Commerce Department's National Marine Fisheries Service -- have announced their opposition, leaving the future unclear.

Westway has become a major environmental battleground, partly because of fears that the huge landfill, which would be a major addition to Manhattan Island, would create serious problems for the area's striped bass.

The 242-acre project, estimated to cost more than $2 billion, would take 10 years to build and include a six-lane underground highway, a park, and a residential and commercial real estate development.

Extending 4.2 miles along low- er Manhattan, the project would create 169 acres of new land in the Hudson River where the bass winter in the warm, shallow waters.

Col. Fletcher Griffis, the Army's district engineer in New York, concluded, after a two-year study, that the landfill will have a "perceptible" but not a significant impact on the bass. He described the fish as having "a high ecological resistance and a high rate of reproduction."

Griffis said the recent sharp decline of Chesapeake Bay bass stocks, which prompted Maryland Gov. Harry Hughes to impose a moratorium on striped-bass fishing, should not be taken as a portent for New York. "The Chesapeake decline appears to be due to chemical pollution," Griffis reported. "Westway would only be a physical change in the habitat."