Westway, the controversial multibillion-dollar highway and development project, received a crucial landfill permit today from the Army Corps of Engineers that is expected to allow construction to begin as early as summer.

A few hours later, opponents who have stalled the 4.2-mile highway for nearly a decade renewed their battle in U.S. District Court.

The 242-acre project, estimated to cost more than $2 billion and be under construction for more than 10 years, is to include a six-lane underground highway, a park and a residential and commercial development on 169 acres of land now covered by the Hudson River.

Col. Fletcher H. Griffis, the Corps' district engineer, and Michael Cuddy, Westway project director for the state Department of Transportation, signed the long-debated permit today.

Last week, the Environmental Protection Agency, the Interior Department's Fish and Wildlife Service and the Commerce Department's National Marine Fisheries Service dropped longstanding opposition to the landfill.

"I am pleased that the resource agencies addressed the merits of the project and did not resort to using technicalities to stop the process," Griffis said.

The federal highway trust fund is expected to finance 90 percent of the cost, but opponents say the fund may run out of money before completion and argue that the money should be diverted to the city's deteriorating mass-transit system.

"Westway is the wrong way," said City Council President Carol Bellamy, a mayoral candidate. "We need the money trade-in, which could build a high-grade replacement roadway and help finance . . . mass-transit improvements."

The three federal agencies had expressed concern that the landfill would harm the Hudson's striped bass, a popular commercial and sporting fish whose numbers have declined sharply in recent years. After a year-long study, Griffis concluded in January that Westway would not have a significant impact on the fish.

Westway foes urged U.S. District Court Judge Thomas Griesa to void the landfill permit, as he had in 1982.