Beijing has been accused of effectively banning Tibetans and other ethnic minorities from obtaining passports, amid a surge in Chinese tourists travelling abroad.
Human Rights Watch says Chinese authorities have created a two-tier system, one for areas populated by the country's ethnic Han majority and another, more cumbersome system for areas inhabited by the country's Tibetan and Muslim minorities.
"If you are a religious minority who lives in a part of the country where most people are minorities, it's virtually impossible to get a passport," said Sophie Richardson, China director at Human Rights Watch.
In most parts of China, a passport must be issued within 15 days, and if there is a delay the authorities must notify the applicant.
But in Tibet and Xinjiang - a region inhabited by 10 million Muslim Uighurs - officials use an older and slower method for passport applications.
Fewer than 10 percent of prefectures in China still use the older system, with all but one inhabited mostly by ethnic minorities, according to the Human Rights Watch report.
In 2012 only two passports were issued in Tibet's Changdu prefecture, known as Chamdo in Tibetan, even though it has a population of 650,000 people.
No figures were available for Tibet overall.
Hundreds of Uighurs were detained last year for illegally entering Thailand, fleeing what rights groups say is religious persecution in China.
The Uighurs claimed to be Turkish citizens, and 181 have been allowed to go to Turkey, with more than 100 others sent back to China.
Meanwhile, mainland Chinese travellers took more than 100 million "outbound" trips last year, according to government figures, although most visited Hong Kong, Macau and Taiwan.
"It's clearly not the case that the state is having massive difficulties issuing passports to some people," Richardson said.