Members of Congress will pressure the Federal Communications Commission in the coming months to toss a telephone "lifeline" to the poor and elderly.

The telephone-lifeline concept, which could require phone companies to offer a minimum number of local phone calls at a low price to low-income customers, has become a high-priority political issue for some members of Congress and consumer groups. They argue that increasing numbers of the poor and elderly cannot afford the higher rates that have been approved since the breakup of the Bell System.

The average cost of telephone installation has increased 27 percent in the past year, according to Gene Kimmelman, legislative director of the Consumer Federation of America. Basic monthly residential service has increased 19 percent, CFA said.

The FCC said it still is studying the impact of rising rates and has no estimate of how many people may be affected. The commission has asked a seven-member panel of state regulators and FCC members to make recommendations by early October. A final decision is expected by the end of the year.

Lifeline proponents are urging the commission to require states to set up some type of discount for local telephone rates.

"We believe that the commission should move expeditiously to adopt and implement a lifeline telephone service program that is meaningful," Rep. Timothy E. Wirth (D-Colo.), chairman of the telecommunications subcommittee, wrote recently in a letter to the FCC.

"The commission should begin to take concrete steps to ensure that local telephone companies offer lifeline programs designed to preserve affordable phone service and meet the public's perceived need for stability in the telecommunications market," Sens. John Heinz (R-Pa.) and John Chafee (R-R.I.) wrote recently to the FCC. Heinz is the chairman of the Senate Special Committee on the Aging.

Consumer groups, along with some members of Congress, want the FCC to require phone companies to subsidize local rates for those least able to afford them, just as phone companies currently pool funds to subsidize service charges in high-cost, mostly rural areas.

However, supporters of the lifeline concept don't want to create a politically vulnerable and unwieldy government "phone-stamp" program that would subsidize phone service for the poor through increases in state and federal taxes. Instead, they want to place the financial burden of administering and subsidizing phone service on the phone companies.

The members of Congress who have been pressuring the FCC said they would rather not seek a legislative solution, but have indicated that they would do so if the FCC takes no action on the lifeline issue. Rep. Mickey Leland (D-Tex.) already has introduced a lifeline bill.

Some supporters of the lifeline concept hope that a congressional debate on the issue will reopen the broader issue of whether deregulation of the telephone industry is in the public interest.

"If the agency fails to establish a lifeline program, critics will have a legislative vehicle for attacking the agency's deregulatory policies," said Kimmelman of the CFA.