Geneva — Grudgingly and reluctantly, the developing countries have agreed to discuss demands by the Reagan administration for a review of the Law of the Sea Treaty at a United Nations conference here.
Publicly, third-world spokesmen insist that there can be no renegotiation of the complex treaty, which was first opened up for discussion at Caracas in 1973. Its present form contains over 300 tightly worded articles covering all aspects of the seas' use.
Privately, however, they have begun talking. Meetings between the US delegation here and 20 other key delegations began Aug. 12 -- outside the normal conference hours and under the leadership of Tommy Koh, Singapore's ambassador to the UN in New York and chairman of the conference.
US officials are confident that these sessions -- about 10 of them have been scheduled -- will be sufficiently representative to gauge which of the American objections to the treaty are negotiable. The Reagan administration then will be able to formulate policy.
Third-world delegates insist that the meetings are informal. They are afraid that any concessions to the United States will lead to the unraveling of the treaty, many of whose provisions were formulated by former US negotiators, including Elliot Richardson and Henry Kissinger.
"We understand that there has been a change of government in the United States," said Inam ul-Haque, the Pakistani chairman of the third world's negotiating Group of 77. "But it should not try to impose its mandate on the rest of the conference. Once we allow the privilege of renegotiation to one delegation, the whole treaty will collapse."
Other delegates are more forthright. "We simply can't be expected to renegotiate major international treaties every time the American president changes," said one.
Initially, the mood here was conciliatory -- to such an extent that the US delegation, in an attempt to forestall controversy, sent an advance copy of the US statement to the Russians before sending it to other Western allies. Many third-world delegates acknowledged that the treaty in its present form would be unlikely to pass the conservative US Congress.
They also felt that the treaty could not function without the participation and financial support of the US, which would expect to contribute roughly a quarter of the costs of the administrative machinery (estimated at $41 million to $53 millon) and initial deep-sea mining (up to $1.5 billion).
But the mood changed abruptly after the statement last week by US delegation head James Malone. Although Mr. Malone was careful not to be specific -- so as to avoid preempting any policy decisions by President Reagan -- the scope of the US concerns left other delegations angry and dumbfounded.
Under the proposed treaty, elaborate machinery would be set up to oversee the exploitation of deep-sea minerals (cobalt, copper, nickel, and manganese), which lie scattered on the floor of the Pacific in small rocks or "nodules." In 1970 the minerals were declared, with US approval, to be "the common heritage of mankind."
The treaty would set up an international "authority" with its own operating arm, called an "enterprise," which would itself begin mining with initial capital and technology from the international community.
US officials are worried by the treaty's curb on deep-sea mining, which limits sea-bed production in deference to land-based mineral producers. In addition, the authority's proposed policymaking body, a 36-member council, raises old US fears about a maverick alliance between the third world and Soviet bloc: Although the US is not guaranteed a seat on the council, the East bloc has at least three.
Convinced that these and other US objections cannot be met without reopening the whole treaty, most third-world delegations are unwilling to give any impression of talking to the US here -- hence their reticence on the informal sessions that began Aug. 12. They hope that a forthright rejection will force the US to consider the risks of staying aloof from the treaty, and encourage the treaty's supporters on Capitol Hill, who have been cowed into silence by President Reagan's landslide victory and the energetic lobbying against the treaty by the mining lobby.
In defense of the treaty, the Group of 77 points of provisions that would, in effect, limit any mischief. In particular, crucial decisions on the council -- such as the rejection of a mining contract awarded to a company -- would require consensus, thus giving the West an effective veto.
The US stands to gain from parts of the treaty that allow for exploitation of the continental shelf beyond the 200-mile economic zone and tough action against foreign vessels that pollute.
At the same time, the treaty curbs the tendency to extend coastal waters by limiting territorial seas to 12 miles and permitting "innocent passage" of warships through 116 strategic straits, territorial waters, and achipelagoes. Submarines, too, are allowed passage through straits, and planes overflight -- the sort of provisions, say delegates, which could prove important in US military planning.
Administration thinking appears to be that the risks of being denied access to the minerals on the sea floor outweigh the guarantee of freedom of navigation , as enshrined in the treaty. But this is hotly disputed by many delegates here.
One pointed out that Brazil pulled in its 200-mile territorial waters to 12 miles last year, proof of the treaty's restraining influence. He also warned that the Philippines is only one of several nations unhappy about allowing warships passage through territorial waters.
This is one of the items important to the US that seems certain to be jeopardized if the US insists on renegotiating the treaty.