Hundreds of Hong Kong secondary students Friday joined the ongoing pro-democracy class boycott protesting against Beijing's refusal to grant the city unfettered democracy.

Student groups are spearheading a civil disobedience campaign along with democracy activists in protest at Beijing's decision to vet who can stand for chief executive -- the southern Chinese city's top post -- at the next election.

University students began a week-long class boycott on Monday, rallying a crowd that organisers said was 13,000-strong on a campus in the north of the city and breathing new life into a movement left stunned by Beijing's hardline stance.

On Thursday night, over 2,000 people took their protest to the residence of Hong Kong leader Leung Chun-ying with the hope of speaking directly to him to voice their concerns about the city's political future. Leung has so far refused to speak with them.

Protests continued Friday morning with more than 500 secondary school students, many dressed in their uniforms, gathering outside the city's main government complex, an AFP reporter said.

"I want real elections not fake ones" student protesters shouted as they approached the city's legislative building.

"The government is ignoring our voices so I think that if we have so many secondary students boycotting the classes maybe then they will be willing to listen to us," Agnes Yeung, a form five student told AFP.

"Secondary students can also see what is happening in society so I think most of them are quite angry towards the decision of the government," Yeung said, adding her parents were supportive of her actions.

"We are here to show that secondary students can also express their opinions on such issues," 15-year-old student Jason Siu said, while wearing his white school uniform.

Organisers said around 4,000 people marched to Leung's house late Thursday, with around 800 people staying overnight.

Leung was reported to have left the house at around 7:30 am (2330GMT) local time from the front gate of government house, as officers fenced in a pocket of protesters.

Last month China said Hong Kongers would be allowed to vote for their leader for the first time in the 2017 election, but that only two or three candidates approved by a pro-Beijing committee could stand.

Britain handed Hong Kong back to China in 1997 under a 'one country, two systems' agreement which allows it civil liberties not seen on the mainland, including free speech and the right to protest.