Hoping to bolster sales of unneeded federal property, the General Services Administration has purchased a mailing list of 2,000 corporation land managers from a New York direct-mail company. In addition, to help lease vacant and unneeded office and warehouse space in both government-owned and commercially leased buildings, GSA will be asking real estate agents to bring in clients for up to a 12 percent commission.

The two separate programs were developed to bolster efforts designed to better manage GSA-controlled property.

In the first instance, GSA has bought a list of corporate land managers to help supplement government land sales agents in disposing of underutilized federal properties. The land sales program in the Reagan administration is designed to raise more than $8 billion over the next five years, with about half of the sales coming from properties controlled by GSA and the rest from the sale of public lands held by the Interior and Agriculture departments.

GSA's Federal Property Resources Service, which is responsible for the land sales program, purchased the list of about 2,000 private-sector executives on the recommendation of property sales officials in its Atlanta regional office. It bought the list from Compilers Plus Inc. of Pelham Manor, N.Y., on machine-readable magnetic tape for $340.

The list includes Washington area companies such as Madison National Bank, First American Bank of Virginia, Drug Fair Inc., Marriott Corp., Riggs National Bank, USAir, Citizens Bank and Trust Co., Donohoe Construction Co. and Woodward & Lothrop. Amtrak is also on the list.

Property Resources Commissioner Carroll Jones said that many of the properties on the GSA inventory are unique and that the direct-mail program is designed to reach investors who otherwise might not be aware of government real estate opportunities. Currently, only the agency's monthly sales brochure -- a state-by-state listing of the properties targeted for sale with a brief description -- is sent to the corporate executives.

In the second instance, another part of GSA -- the Public Buildings Service -- is trying to better utilize those federal properties that the government is keeping.

In the past, GSA has been heavily criticized by Congress and other auditors for leaving vast blocks of office and warehouse space vacant. Rather than continue that practice, an ambitious outleasing program has been developed that will try to advertise for tenants in blocks of space that can't be filled by government agencies and can't be returned to building owners.

To help spur interest in those blocks of space, GSA has determined that it can pay commisions of up to 12 percent of commercial real estate agents who help them fill unused blocks of both government-owned and commercially leased space controlled by GSA. Public Buildings Commissioner Richard O. Haase said "we expect brokers to stimulate tenants."

In using real estate agents, GSA is "trying to get away from the competitive bid process" -- in effect, looking for loopholes in the law that will allow it to deal directly with a real estate agent who is helping to fill space that otherwise would be costing the government money, Haase said.

"Our first goal, for commercially leased space, is to have the building owner get us out of our lease and take it back," Haase said. "We don't want to compete with them. But if they won't take it back, we may have no other choice than to try to make some money on it."

He said that commissions on these properties probably would be larger on the smaller blocks of space because of the effort needed to consumate the deal. The commissions will be based on the going rates in each area of the country up to a federally authorized limit of 12 percent.

Rather than put up specific properties and have real estate agents compete for the right to outlease the space, or to do what would amount to a multiple listing with real estate agents, Haase said he would rather have the private sector "make me an offer. We'll give them 30 or 60 days, and if they do it, then we'll have a lease."