BEIJING » Flush with cash and eager to see the world, millions of middle-class Chinese spent the 10-day Lunar New Year holiday that ended Monday in places like Paris, Bangkok and New York. Last year, Chinese made a record 83 million trips abroad, 20 percent more than in 2011 and a fivefold increase from a decade earlier.

Sun Wenguang, a retired economics professor from China’s Shandong province, was not among those venturing overseas, however. And not by choice. An author whose books offer a critical assessment of Communist Party rule, Sun, 79, has been repeatedly denied a passport without explanation.

"I’d love to visit my daughter in America and my 90-year-old brother in Taiwan but the authorities have other ideas," he said. "I feel like I’m living in a cage."

Sun is among the legions of Chinese who have been barred from traveling abroad by a government that is increasingly using the issuance of passports as a cudgel against perceived enemies — or as a carrot to encourage academics whose writings have at times strayed from the party line to return to the fold.

"It’s just another way to punish people they don’t like," said Wu Zeheng, a government critic and Buddhist spiritual leader from southern Guangdong province whose failed entreaties to obtain a passport have prevented him from accepting at least a dozen speaking invitations in Europe and North America.

China’s passport restrictions extend to low-level military personnel, Tibetan monks and even the security personnel who process passport applications.

"I feel so jealous when I see all my friends taking vacations in Singapore or Thailand but the only way I could join them is to quit my job," said a 28-year-old police detective in Beijing.

Lawyers and human rights advocates say the number of those affected has soared in recent years, with Tibetans and Uighurs, the Turkic-speaking minority from China’s far west, increasingly ineligible for overseas fellowships, speaking engagements or the organized sightseeing groups that have ferried planeloads of Chinese to foreign capitals.

Although the government does not release figures on those who have been denied passports, human rights groups suggest that at least 14 million people — mostly those officially categorized as ethnic Uighurs and Tibetans — have been directly affected by the restrictions as have hundreds of religious and political dissidents. A representative of the Exit-Entry Administration of the Public Security Bureau declined to discuss the nation’s passport policies.

The seemingly arbitrary restrictions also affect overseas Chinese who had grown accustomed to frequent visits home. Scores of Chinese expatriates have been denied new passports by Chinese Embassies when their old ones expire, while others say they are simply turned away after landing in Beijing, Shanghai or Hong Kong. After finding their names on a blacklist, border control officers will escort returnees on to the next outbound flight. Even if seldom given explanations for their expulsions, many of those turned away suspect it is punishment for their anti-government activism abroad.

"Compared to other forms of political persecution, the denial of the right to return home seems like a small evil," said Hu Ping, the editor of a pro-democracy journal in New York who has not seen his aging parents in decades. "But it’s a blatant violation of human rights."

Even those carrying valid passports are subject to the whims of the authorities. On Feb. 6, Wang Zhongxia, 28, a Chinese activist who had planned to meet the Burmese opposition leader Aung San Suu Kyi, was barred from boarding a Myanmar-bound flight from the southern city of Guangzhou. Four days earlier, Ilham Tohti, an academic and vocal advocate for China’s ethnic Uighurs, was prevented from leaving for the United States.

Tohti, who was set to begin a yearlong fellowship at Indiana University, said he was interrogated at Beijing International Airport for nearly 12 hours by officers who refused to explain his detention. Speaking from his apartment in the capital, Tohti said Uighurs have long faced difficulties in obtaining passports but that the authorities have made it nearly impossible in recent years. "We feel like second-class citizens in our own country," he said.

For decades after the Communists came to power in 1949, most Chinese could only dream of traveling abroad; the handful who managed to leave often escaped by evading border guards and swimming across shark-infested waters to what was then British-ruled Hong Kong. As China opened up to the outside world in the early 1980s, the government began providing passports and exit visas to graduate students with acceptance letters from universities overseas.

All that changed in 1991, when Beijing issued new rules allowing Chinese to join group tours to "approved destinations" in Southeast Asia, and two years later, to the United States and Europe. These days, members of China’s ethnic Han majority can generally obtain a passport in 15 days.

But the rules are more arduous for Tibetans and Uighurs, who must win approvals from several layers of bureaucracy — including provincial authorities, the applicant’s hometown public security bureau, and for students, university administrators. Tsering Woeser, a Tibetan writer who has tried and failed to get a passport since 2005, said the denials are driven by fears that once abroad, minorities will speak out about China’s repressive ethnic policies or link up with exile groups.

"For the Han, getting a passport is as easy as buying a bus ticket," she said. "But for Tibetans it’s harder than climbing to the sky."

Since April, the authorities have been confiscating passports from Tibetans lucky enough to have them in the first place. According to documents obtained by Human Rights Watch, the police in Tibet are also required to interrogate returnees and determine whether they have broken a signed pledge not to engage in activities that "harm state security and interests" while outside the country.

The new procedures were introduced after thousands of Tibetans attended a religious gathering in India that included an appearance by the Dalai Lama, the spiritual leader whom Beijing considers a separatist. Tibetan exiles say the restrictions also seek to limit information about the recent spate of self-immolations from reaching the outside world.

The frustrations of those affected by the tightened rules received a rare public airing after a 21-year-old Uighur college student blogged about her unsuccessful attempt to get a passport. The student, Atikem Rozi, said the repeated rejections had dashed her hopes to study abroad and broken her spirit.

"Whenever the subject of a passport is mentioned, it brings me to tears," Rozi, a student at Minzu University in Beijing, wrote last month. "My passport is still a riddle, a luxury."

Widely forwarded, the blog posts prompted favorable coverage in one Chinese publication. But they also drew unwanted attention from the domestic security agents in Xinjiang, who during six hours of questioning this month suggested she was "politically unqualified" to go abroad because she had used her microblog to complain about discrimination against Uighurs.

The inability to travel has driven many Chinese to take desperate measures. In 2011, Liao Yiwu, a poet and author from the southwest city of Chengdu, escaped overland to Vietnam after the authorities rebuffed his passport application more than a dozen times and then threatened him over plans to publish a book overseas. He now lives in exile in Germany.

Wu’er Kaixi, who was No. 2 on the government’s most wanted list after he organized student protests in Tiananmen Square in 1989, has spent the last several years trying to get himself arrested by the Chinese authorities in an attempt to return home to see his aging parents. Kaixi, who lives in Taiwan, has tried crashing through the gates of the Chinese Embassy in Washington and he once flew to Chinese-administered Macau and offered himself up to the police. He was promptly put back on a plane and sent home.

"It is unbearable to contemplate the idea that I may never see them again," he wrote last year of his parents, who have also been barred from leaving China. "This is barbaric and cruel behavior by the Chinese government."

© 2013 The New York Times Company