A special board of federal and state regulators yesterday approved a compromise plan that would add a $1-a-month "access fee" to residential telephone bills next June, increasing to $2 a month in 1986.

The proposal, which is expected to be ratified by the Federal Communications Commission next month, represents a significant modification of the commission's proposal last year to impose access charges of as much as $4 a month. Agency officials and some consumer advocates said yesterday they thought the plan would have a reasonable chance of winning approval from the Congress.

"Consumers have benefited tremendously," said Samuel Simon, director of the Telecommunications Research and Action Center. "This is tremendous backtracking by the FCC; it's a repudiation of their initial decision. We think Congress really ought to take a look at it."

FCC officials have said the access charges -- which would be tacked on to monthly phone bills sent out by local phone companies -- are necessary to end a longstanding system of cross-subsidies in which local rates have been kept artificially low at the expense of overpriced long-distance rates. By imposing access fees -- or "subscriber line rates" as the FCC now calls them -- the FCC argues it would be able to lower long-distance rates beyond the 6.1 percent reduction it approved for American Telephone & Telegraph Co. last year.

In the past, however, state regulators and members of Congress have argued that the fees, coming on top of higher local rates sparked by last year's AT&T breakup, would be an intolerable burden on low-income users. As a consequence, the new proposal reduces the level of access charges to $2 in 1986 and provides for discounts of up to $2 monthly for low-income consumers as defined by state and local governments.

In addition, to prevent large business users from "bypassing" the local telephone network by setting up their own telecommunications systems, the joint board proposal recommends a special rate discount for big businesses. If a state regulatory body concludes that the discount is needed to keep the business on the network, residential access charges could increase to a total of $2.35 per month to help cover the shortfall caused by the discount.

The joint board that drafted the access charge plan is a special body of FCC members and state regulators who make recommendations to the full FCC. Although approval from the commission is considered virtually automatic, Congress still has the power to veto any of the agency's actions.