Montgomery County's office of consumer affairs, responding to citizen complaints, has filed suit against the Chicago-based developer American INVSCO Corp. for allegedly failing to repair and refurbish one of the largest luxury condominium complexes in the county.

The suit says that Invsco and its subsidiary, Rockville Grosvenor Inc., failed to repair or improve sidewalks, roads, curbs, swimming pools and tennis courts at the 1,050-unit Grosvenor Park complex on Rockville Pike. The company began selling the units, which cost from $50,000 to $300,000, in 1979.

INVSCO was also the developer of the 1,072-unit Promenade complex in Bethesda, but defaulted on millions of dollars in loans on that project and lost ownership to Chase Manhattan Bank in September.

The county became involved in the Grosvenor Park case after tenants made a list of repairs and improvements that had been promised in their contracts but which the company failed to provide.

John Gifford, vice president of the Grosvenor Park II condominium association, said yesterday that tenants tried first to negotiate a settlement with INVSCO.

"We couldn't get anything from them," Gifford said. "We have had to make a number of repairs at our own expense."

Gifford said tenants called the county consumer affairs office, which investigated and found the tenants' complaints legitimate. The county attorney's office then conducted an investigation, which led to last week's lawsuit filed in Montgomery County Circuit Court.

Officials at INVSCO in Chicago did not respond to calls yesterday.

Gifford said that in addition to incomplete work on pavement surrounding the complex, the company refused to repair a concrete stairway used as a fire exit in one of three high-rise buildings. The condominium owners closed the stairway but then had to pay for the repairs when the fire department ordered the exit reopened.

The condominium owners also paid for a costly swimming pool repair, Gifford said.

The Grosvenor Park condominiums were designed as part of an expansive complex that includes a pond, a brook and a private security force.