Negotiations are to open in Peking this month on the future of Macao, the Portuguese island exclave set to return to Chinese rule alongside Hong Kong in a process that will end centuries of European colonialism in the area.

The two governments announced the talks for the last week of June in a joint statement issued after a year of preparatory consultations on the reestablishment of Chinese administration in the world's most densely populated territory after more than 400 years of Portuguese colonial rule.

Deputy Foreign Minister Zhou Nan, who negotiated the resumption of Chinese sovereignty over nearby Hong Kong, will head Peking's delegation. Rui Medina, a career diplomat and former ambassador to the United Nations, is to be Lisbon's chief negotiator.

Portugal is expected to relinquish Macao when Britain's lease on Hong Kong expires in 1997, according to officials here. But they said the different pace of economic development in the two territories and historic disparities meant the Peking negotiations were not likely to result in a carbon copy of the Hong Kong agreement.

Unlike the talks on Hong Kong, an immensely richer and more advanced neighbor, little tough political bargaining is expected over the future of Macao. A Chinese mandarin gave the territory to the Portuguese in 1557 for their help in fighting pirates. But when the left-wing government that emerged from Portugal's 1974 "Revolution of the Carnations" offered to return Macao, Peking said the time was not ripe.

Colonial rule officially ended in 1979 when Lisbon and Peking established diplomatic relations and agreed to recognize Macao as Chinese territory under Portuguese administration. No deadline exists for a Portuguese withdrawal. As one diplomat here said, "Portugal seems to be in more of a hurry to give up Macao than China does to get it back."

Peking has indicated that it will preserve the capitalist economy of Macao under the same "one country, two systems" formula it has pledged to maintain in Hong Kong for 50 years after the resumption of Chinese sovereignty.

"The two territories are likely to be used as a springboard for introducing free market enterprise into southern China," said Cecilia Jorge, a Macao journalist who now monitors the territory from Lisbon. "China has been experimenting with capitalist-style economies in several southern areas since the 1970s," she said, "and importing these two ready-made and thriving examples will give considerable impetus to these projects."

Macao, a six-square-mile territory with a population of 450,000, produces textiles, toys and electronic components. But the integration of its main source of income poses a delicate problem for Peking. Gambling casinos, banned in China, account for 40 percent of earnings and form the mainstay of the tourism industry.

Analysts here also say that the paternal style of Portuguese colonialism has left Macao without a class of bureaucrats, technicians and professionals to run the territory when the 4,000-strong Portuguese administration eventually withdraws. About 97 percent of the population is of Chinese origin, including many who fled the Chinese revolution. Many who acquire professional skills emigrate.

Nationality is expected to be one of the thorniest issues of the talks. Unlike Britain, whose Hong Kong citizens have no right of abode in Britain, Portugal does not recognize different categories of citizenship. Any Macao resident who can speak Portuguese and be self-supporting can apply for a Portuguese passport that carries with it the right to live in Portugal and eventually any country within the European Community.