A plan to streamline the House International Relations Committee has stirred concern among human-rights activists because the proposal would eliminate what has become the most prominent forum in Congress for attacking rights abuses.

At issue is the future of the committee's international organizations subcommittee. Under the chairmanship of former representative Donald M. Fraser (D-Minn.), the subcommittee had emerged as the spearhead of efforts by congressional liberals to urge a more activist human-rights policy on the Carter administration.

But Fraser, who gave up his House seat in an unsuccessful run for the Senate, isn't in the new Congress. That has left the subcommittee without an incumbent chairman to protect its turf. Congressional sources say it has become a target of efforts by the chairman of the parent International Relations Committee, Rep. Clement J. Zablocki (D-Wis.), to pare the number of subcommittees.

Accodring to the sources, Zablocki is responding to pressure from the House Democratic leadership on committee chairmen to cut staff and expenses.

While stressing that Zablocki's plan is still tentative and subject to approval by the committee's Democratic majority, the sources said he wants to reduce the nire subcommittees to seven.

Out-of consideration for those subcommittee chairmen who are returning, he had focused on the two subcommittees that are currently without chairmen: international organizations and the international development subcommittee, which had been headed by Michael Harrington (D-Mass.).

Some sources say the functions of these subcommittees can be redistributed more eastly than those of the subcommittees concerned with specific geographic areas such as Europe or the Far East.

Where the Fraser subcommittee is concerned, partisans of the consolidation plan deny any attempt to deemphasize congressional attention to human-rights questions.

Instead, they argue that these questions can be addressed in subcommittees dealing with geographic regions. In addition, they say, the Fraser subcommittee's involvement in rights issues was primarily a reflection of his personal interest, so even if the subcommittee were to continue under a new chairman, there is no guarantee that it would pursue the same paths.

However, these arguments are rejected by many liberals in Congress and by their supporters in the myriad human-rights organizations anxious to preserve a sympathetic congressional forum for their views.

They contend that, as a result of Fraser's past efforts, the subcommittee already is symbolically established as Congress's primary source of rights legislation and its principal watchdog over worldwide rights violations.

To redistribute these functions among other subcommittees with other interests, they contend, would pose too great a risk of fragmenting and diluting congresional atention to rights problems.

In addition, the subcommittee's supporters note, the two committee members next in line to become chairman -- Reps. Stephen J. Solarz (D-N.Y.) and Don Bonker (D-Wash.) -- are both liberals with reputations for activism who could be expected to keep the subcommittee moving in the direction set by Fraser.

Solarz, who is thought to have ambitions about eventually moving to the Senate, is described by committee sources as especially anxious to have the subcommittee chairmanship. Some say he already is sounding out liberals within the Democratic majority on the full committee about fighting any attempt to do away with the subcommittee when the members caucus this week or next.