The year-long public campaign might have looked familiar to someone from the American Southwest:

"A Million Undocumented People Have Entered the Country in Less Than a Year," read one Caracus newspaper headline. "Venezuela: Occupied Country?" read another. A third cried: "Leprosy, Veneral Disease, Malaria, and Yellow Fever: Diseases of the Undocuments."

"In Venezuela, however, the immigrants they worry about -- the domestic servants, the unskilled laborers, the lower paid farm and factory workers -- are other South Americans, the vast majority of them Columbians who come in through the "green highways" of the long Venezuelan border to take advantage of Venezuela's oil-swollen economy.

With higher wages, more jobs, and the highest gross national product per capita on the continent, especially since the 1973 OPEC oil price increase, Venezuela has begun to chafe at its image as the rich, open-doors neighbor to the north.

For much of the past year, as Venezuela mounted its campaign to count and register the immigrants living inside its borders, there was talk of the huge numbers that would be found -- 3 million illegal immigrants, one official speculated, in a nation of 16 million people.

As publicity about the program heightened, so did general resentment against Colombians, particularly as Venezuela feels the deliberate economic slowdown that President Luis Herrera Campins' administration has imposed to curb the lavish spending of his predeccessor and reduce the foreign debt.

The rising crime rate, the increase in unemployment (now unofficially estimated at up to 15 percent), the proliferation of sagging wood and red brick Venezuelan slums -- all were blamed at least partly on the new immigrants from the west and south.

"It's always the Colombians' fault," said a soft-spoken hotel maid who immigrated eight years ago from Bogota. "They say we're something terrible, that the women come here to prostitute themselves, that the slums are all full of Colombians. And you have to agree to whatever they want to pay you."

Married to a Venezuelan now, and settled in a small house surrounded by the hillside squatters' homes, the Colombian woman is not particularly impressed with Venezuela's comforts. "I am working, and I don't have many problems," she said. "The pay is better here, and there are many more jobs. But it costs so much for your house and food that I think sometimes I might be costs so much for your house and food that I think sometimes I might be better off in Colombia."

Fueling the tension, especially last autumn, was the most recent impasse in a longstanding feud between Colombia and Venezuela. At stake is the international division of the Gulf of Venezuela, a wide bay off the Caribbean Sea that lies just north of what had traditionally been Venezuela's richest oil-producing region. Although there is no reliable estimate as to the potential gulf oil reserves -- or even whether the gulf has oil at all -- guesses have run into the billions of barrels.

Although the gulf is almost entirely surrounded by Venezuelan land, the southwestern shore is part of a long Colombian peninsula. With Colombia basing its claim on that shore, and Venezuela convinced that the gulf is its own, negotiators have been trying for 13 years to settle the dispute.

Last October they came up with a draft treaty that laid out an international dividing line and specified that any oil reserve extending to both sides should be divided equally. The treaty was widely accpted in Colombia, but in Venezuela it provoked considerable argument, and President Herrera Campins has shelved it until later this year. All over Caracas, on spray painted walls, big black letters read: "No to Colombia -- the gulf is Venezuelan."

Two weeks ago, amid this less than cordial atmosphere, the four-month immigrants' registration drive ended.Neither the program nor its follow-up, a national effort to deport all immigrants who failed to register, have quite lived up to expectations. According to Enrique Aristeguieta, Venezuelan vice minister of interior relations, 350,000 illegal immigrants, mostly Colombians, accepted the government's offer to apply without penalty for one-year residence documents.

That is a small fraction of the figures being tossed around last year. If overwhelming numbers of still undocumented immigrants remain in Venezuela, the police have yet to find them.

Aristeguieta thinks now that there may be 150,000 more immigrants without papers in the country, but acknowledged that as of last week, most of the people picked up without documents turned out to be Venezuelans or legal residents who had simply left their documentation at home. "Of thousands of people they have detained for not carrying identification," he said, "we haven't expelled even a hundred from Caracus."

The search for the undocumented continues, however, as police board buses and stop automobiles to check for the national identification that all Venezuelans are required to carry. Colombian officials have made some irritated public statements about "hysteria" and "xenophobia," and at one point complained that Venezuela was deporting undocumented Peruvians and Ecuadorans into Colombia, but relations between the two countries otherwise have remained polite.

During the coming months, Venezuelan officials say they will try to formulate a coherent general immigration policy, something the country has not had since 1958, when it abandoned the liberal immigration program that had attracted thousands of Europeans. Meanwhile, Aristeguieta said the Colombian borders would be more carefully patrolled, and that tourist visas -- a common entry ticket for those intending to stay on -- would be granted only to real tourists.

Asked how one made that distinction, Aristeguieta said most border officals could tell: "A person who doesn't know how to sign his name is not a tourist."