The Chicago Planning Commission has recommended zoning changes that clear the way for a downtown complex that would be one of the world's highest-density office projects.

The project, proposed by Liberty Property Co. of Dallas, would include three 60-story office towers surrounding a glass-enclosed grass plaza across from the Sears Tower. The three buildings would contain 4.2 million feet of office space, about the same as the Sears Tower.

A citizens watchdog group that opposes the project, the Metropolitan Planning Council, criticized the planning commission's action Monday night, saying the commission acted too quickly in approving the zoning change.

"This is one of the largest developments proposed for Chicago, or any city anywhere," said Lewis Manilow, a member of the council's board.

He complained that the commission acted too hastily in hearing the zoning request, debating it and approving it all in one meeting.

The commission approved the zoning request on a 5-to-1 vote. "This thing is sailing through like a hot wind off the desert," said Leon Despres, the lone dissenter.

The project is supported by a majority of the City Council, which will have the final say on the matter later this month. The project also is supported by Mayor Harold Washington's planning department.

Developers said they will spend $288 million on the first tower and atrium, with completion targeted for 1989. The other two towers would be built during the following eight years.

Indiana and New York led the country in increases in sales of existing homes from October through December, while the price of a home rose the fastest in Boston, according to a survey by the National Association of Realtors.

The real estate trade group compared sales levels and prices in the last three months of 1985 with the same period in 1984.

The association's survey found that sales soared 81.4 percent during the final three months of last year in Indiana and 51.4 percent in New York.

Analysts said the boom in Indiana primarily reflected a strong housing market in Indianapolis and its suburbs.

Other states with big sales gains were Florida, up 50.3 percent; Vermont, up 48.7 percent; and Arkansas, up 47.3 percent.

Nationally, sales increased 25.4 percent in the fourth quarter to a seasonally adjusted annual rate of 3.8 million units compared with the sales rate in the final three months of 1984.

In all, 16 states and the District of Columbia recorded sales increases of more than 30 percent during the October-December period, with economists for the association crediting lower interest rates for much of the sales gain.

During the same period, the median price of an existing home rose by 3.8 percent to $74,700 in the fourth quarter, compared with $72,000 in the fourth quarter of 1984.

The increase was in line with the rise in consumer prices during the same period.

But some parts of the country, in particular the Northeast, showed increases in prices far above the nationwide average.

According to a survey of 43 metropolitan areas done by the association, home prices shot up 38.2 percent in Boston to a median price of $144,800.

This was the sharpest increase and the highest median price for any of the regions surveyed. The Washington-area figure was $97,300, up 6.1 percent.

"Very strong demand for housing in the Northeast, largely because of the strong financial services and high-tech industries, has put extreme upward pressure on home prices in that area," the association survey said.

Not all areas of the country participated in the housing boom last year.

The survey found that eight states experienced declines in home resale activity in the fourth quarter with the declines reflecting the depressed farm economy and the slumping energy industry.

The biggest drop was a 26.3 percent fall in sales activity in Louisiana, followed by a 21.3 percent decline in South Dakota.

Other states with sales declines during the fourth quarter compared with a year earlier were Iowa, Kansas, Nebraska, Idaho, Montana and Oklahoma.

Construction permits for single-family homes climbed 56.5 percent in January in the Baltimore metropolitan area, the Regional Planning Council said. The council said, however, that the building of multi-family units in the area continues to decline.

The most new housing permits were issued in Anne Arundel, Baltimore and Howard counties, the council's figures showed.

The council said single-family construction permits last month totaled 982 units, compared with 627 units for the same month in 1985.

Multi-family housing construction decreased 50 percent to 212 units from 424 for the same period of 1985.

All 212 of the multi-family units are planned for the Columbia area, where garden apartments will be built with tax-exempt financing.

IN THE BUSINESS . . . Balcor Co., an Illinois real estate investment and management firm, has bought the 228,000-square-foot office building at 1275 K St. NW from the project's developer, the Rubin Group, in an all-cash transaction for $43.9 million. The building is about 80 percent leased . . . More than 12 million square feet of new office space was leased last year in the Washington metropolitan area, which outpaced New York, Chicago, Houston and Los Angeles for the second year in a row, according to commercial leasing agent Julien J. Studley Inc. Stephen Goldstein, senior vice president and manager of its Washington office, said 11 million more square feet of new and old space will be available for leasing in the next three years, a supply that will outpace demand . . . Walker and Co. has completed a 100,000-square-foot building at Parkridge Center in Reston . . . Oxford Development Corp. has formed Oxford Mortgage Securities Corp., which will issue securities backed by Oxford products . . . General American Real Estate & Development is planning to build a 12-story, $16 million condominium building in Columbia called the Watermark. Construction on the 76-unit building is expected to start soon, with completion in 15 months. Prices are expected to range from $120,000 to $300,000. . . Veeres Inc., a real estate development, investment, management and consulting firm, has opened its doors at 2070 Chain Bridge Rd. in Vienna, with A. Wilhelm Veenhuysen as president . . . Robert Bell has been elected chairman of the Montgomery County Housing Opportunities Commission . . . The Deauville Hotel in Miami Beach is selling condominiums with an unusual twist. Buyers can resell their units back to the developer for three times their cash investment if casino gambling is approved in a Nov. 5 referendum.

PERSONNEL FILE . . . Anthony H. Harrigan III has been named a vice president of the real estate financing and investment counseling firm of Ivor B. Clark Co. . . . CHK Architects and Planners has named three new partners -- Tunca Iskir, John T. Stovall and Kenneth A. Weinstein . . . National Corporation for Housing Partnerships has promoted Linda G. Davenport to senior vice president, general counsel and corporate secretary and Christopher B. Hanback to vice president and deputy general counsel . . . Real Estate Appraisal Services Inc. has promoted Beverlie M. Pogue to vice president of administration.