Hong Kong student leaders have announced plans to take their protest to Beijing, in the hope to have their plea for democracy heard by top Chinese officials.

Eason Chung, a prominent member of Hong Kong Federation of Students, said he and fellow activists Alex Chow and Nathan Law have bought plane tickets for the Chinese capital, where they will seek a meeting with Premier Li Keqiang.

"A few of us powerless students will not flinch in the face of a powerful authority," the federation said in a statement.

However there are no guarantees China will allow them in upon landing.

A student activist with another group was barred entry in the Chinese city of Shenzhen last week, over accusations he took part in "activities against national security," AFP reported.

The three Federation students had asked Hong Kong's government and the city's former leader Tung Chee-hwa to help them arrange a meeting but their request was turned down.

"When those bridges between the Hong Kong government and Beijing rejected all our demands, we think they are not doing their due responsibility, so we'll go ourselves," said Chung.

Mass demonstrations in the territory started this summer, after Beijing backtracked on a pledged to allow Hong Kongers to democratically elect their leader.

China, which has ruled over the former British colony according to the so-called "one country, two systems" policy since the handover in 1997, had promised to grant universal suffrage to the city by 2017.

The vote to replace current leader Leung Chun-ying will eventually be the first in which voters will directly choose the winner.

However, pro-democracy activists say that China hasn't kept its promises, as candidates will be preventively screened by a pro-Beijing committee that will most likely ban opposition leaders from running.