HONG KONG (Reuters) - About one in six people in Hong Kong want the special administrative region of China to become independent of the mainland, a university poll has shown, although few think it will ever happen.

According to the poll, released on Sunday, 17.4 percent somewhat supported or strongly supported independence for Hong Kong when its 50-year "one country, two systems" agreement, under which it is governed by Beijing, expires in 2047.

Another 22.9 percent were ambivalent, according to the poll, which was conducted by The Chinese University of Hong Kong's Centre for Communication and Public Opinion Survey. Another 57.6 percent were somewhat or strongly against the idea.

Hong Kong, a former British colony, was handed back to China in 1997 under an agreement that gave ultimate control to Beijing but promised Hong Kong greater freedoms and separate laws for at least 50 years.

Tensions have grown over the past two years, with activists saying China is failing to abide by its agreement while Beijing says the activists are operating outside the law.

The two sides have clashed over months-long pro-democracy street demonstrations, flash riots and government appointments viewed by some as controversial.

A small but vocal minority of activists has also called for outright independence from China and has fielded candidates for the election to Hong Kong's lawmaking body in September.

City officials sparked a row by saying candidates who failed to sign a declaration that Hong Kong is an "inalienable" part of China and who promoted or advocated independence could be deemed ineligible.

Chinese Vice President Li Yuanchao said while meeting a Hong Kong youth delegation in Beijing on Monday that young people in the territory should "ardently love our country from the bottom of our hearts", state news agency Xinhua reported.

Despite the support for independence in the poll, few see it as a real possibility. According to the poll, fewer than 4 percent of respondents thought it was possible.

The poll was conducted over the telephone with 1,010 Cantonese-speaking residents aged 15 or above from July 6-15.

(Reporting by Clare Baldwin and Sharon Shi; Additional reporting by Ben Blanchard in BEIJING; Editing by Paul Tait)