The most unsettled frontier in international life today is the line where the sovereign rights of nations are challenged in the name of the human rights of their citizens. It'll be made even more unsettled by a new report that argues that an international agreement should be written binding governments to provide relief for victims of natural disasters in their territory.

The demamd arises from the dolorous fact that some nations, perhaps an increasing number, are political reasons averting their official gaze from their citizen's suffering in both slow-moving disasters, like droughts and epidemics, and sudden disasters, like floods and hurricanes.

Either the government does not wish to advertise its inability to care for its own citizens by asking for international aid, or it fears a drop in tourism or earnings from other sources, or it has a grievance against people from the affected region or sector, or something.

The leading case remains that of Ethiopia in 1973, when now-gone Selassie government covered up a drought and famine that may have claimed as many as 100,000 lives. Similar coverup charges are currently being leveled against Ghana and Haiti, according to the Inter Dependent, published by the private United Nations Association in New York.

The publication suggests that the shaky Ghana regime's much-ballyhooded campaign of self-reliance makes it awkward for the government to admit the famine exists and embarrassing to request foreign assistance."

Why hasn't the United Nations steeped in? "We are not a world government," a key U.N. official said. "National soverignty is a fact of international life which we must respect."

THaiti, meanwhile, seems to have played down a drought that has produced famine conditions in its proverty-striken north west hinterland. Once again, a regime determined to put on its best face for international inspection stands accused of slighting the interests of its own citizens.

The dimensions are further suggested by a UNA report that, from 1972 to 1976, three-fourths of the 42 countries considered the poorest in the world had major natural disasters requiring some measure of international assistance, and that in a third of 89 disaters in that period, political considerations are alleged to have limited the local government's response.

International relief officials now refer to the "second disaster" in relief operations: Inadequate government response adds to nature's toll.

This is the situation confronted by the new UNA report, issued by a group including such heavies as Orville Freeman, George Ball and Hubert Humphrey, and entitled "Acts of Nature, Acts of Man: The Global Response to Natural Disasters."

It's full of thoughtful practical suggestions (worked out, for a change, in consultation with many of the people who'd have to carry them out) to improve the technological, logistical, financial and administrative aspects of international relief. Its premise is that merely keeping their nose above water so taxes the resources of most poor countries that they have a legitimate claim on extra help for that admittedly arbitrary part of their woes attributable to natural disasters.

The more questionable part of the UNA report lies in its proposal for an international agreement specifying the "rights and obligations" of governments in assisting victims of natural disasters. In evident dismay, the report notes that none of the articles in the existing Geneva Conventions regulates the behavior of governments in disaster situations. Back to the drafting board in Geneva, the UNA advises.

But is that trip really necessary? It is hard to aviod the feeling that, worthy as this new cause may be, there is a surfeit of rights and conventions on the international books, and the problem is not to add new ones but to enforce old ones.

I suspect that even the most ardent humanitarians and internationalists among us would agree that there is a finite limit to the number and kind of global obligations that can be heaped up on any one nation's plate. Some selectivity is required. If these pledges are to have any life beyond paper.

And strictly from a practical viewpoint, is it wise to frame every newly perceived international problem in formal and legal and official terms? Should not some room be left, especially in nonroutine areas like disasters where unofficial personal, national and international efforts have traditionally played a large role, for spontaneous and compassionate response?

The UNA report itself concedes as much: "Many experts in the disaster relief field - even among those who acknowledge the importance of political problems in the relief process - believe that existing organizations and governments can best deal with this problem in an informal manner." Let them.