Police used pepper spray to disperse crowds of Hong Kongers demonstrating against Chinese President Hu Jintao Saturday, ahead of the 15th anniversary of the territory's handover amid tight security.

On the second day of his visit to the former British colony, hundreds of protesters demanding an investigation into the death of a leading Chinese dissident rallied near Hu's hotel that was surrounded by giant barricades.

Hundreds of demonstrators, who tried to breach the giant blue and white barriers, were targeted with pepper spray as protesters chanted anti-Beijing slogans and unfurled a huge banner with the Chinese character "injustice".

Hu's visit comes as discontent toward Beijing surges to a new high, and his visit has drawn sneers and ridicule from Hong Kongers.

Some reporters, including three AFP journalists, at the scene were also hit by pepper-spray while another agency reporter was manhandled.

One other local reporter was briefly held after asking Hu about the Tiananmen Square crackdown Saturday.

There was palpable anger against the death of Chinese dissident Li Wangyang, who was jailed for more than 22 years over the 1989 Tiananmen democracy protests.

He was found dead in his hospital ward in China earlier this month, where his family said he died under suspicious circumstances.

There is an unusually tight security cordon around Hu's five-star hotel and a convention hall where key celebrations, including the inauguration of the city's new leader, will be held.

Police manned every intersection and building entrance nearby, part of an enhanced security presence visible around the city.

The barricades are more than two metres (6.5 feet) high -- a size last used during protests against the World Trade Organization in Hong Kong in 2005 -- and are likely to defy Hu's wish to "walk more" and "see more" in the city.

Metal fences set up to keep potential demonstrators in a so-called "petition zone" and "protest zone" are so far away that Hu and his delegation are unlikely to see or hear any protests, a fixture of Hong Kong's daily life.

"Are we celebrating the handover anniversary or staging a war?" a Facebook user wrote.

Other users said the Asian financial hub, which returned to Chinese rule in 1997, had been turned into a "city of barricades", while some likened the measures to the Great Wall of China and the Berlin Wall.

"The Berlin Wall separated East and West Germany, let's hope this wall of barricades can separate Hong Kong from China forever," one user wrote, underscoring a sense of growing discontent among Hong Kongers toward Beijing.

"Get out of Hong Kong!" one writer told the Communist Party and the People's Liberation Army (PLA) in a post on the Facebook page of the Hong Kong chief executive, which was flooded with anti-Beijing comments.

The remarks came a day after Hu presided over a military ceremony that shed a rare light on the secretive PLA garrison stationed in Hong Kong.

Another, writing on the same page, said that Beijing was "really out of touch with HKers. Can't blame... them, dictators care not, know not."

The right to protest is part of the cherished freedoms enshrined in the "one country, two systems" model that has applied to Hong Kong since its return to Chinese rule.

The city of seven million people maintains a semi-autonomous status with its own legal and financial system.

Police said they would respect the right to protest during Hu's visit, after they were criticised for heavy-handedness during a visit by Chinese Vice Premier Li Keqiang last year, prompting a special inquiry.

The director of Hong Kong Human Rights Monitor, Law Yuk-kai, criticised the security measures which he said was an attempt to shield the Chinese leader from any "embarrassing demonstrations" and that the city was "under siege".

On Saturday Hu visited the site of a future cruise ship terminal in Kai Tak, where the city's airport used to stand, but his highly choreographed visit was briefly disrupted by a question over the Tiananmen crackdown on June 4, 1989.

"President Hu, Hong Kong people want to see justice for June 4. Did you hear that?" a local journalist shouted repeatedly at Hu from behind the security cordon, before he was taken away briefly by security personnel.

Hu's first stop after arriving Friday was a parade in front of the massed ranks of China's secretive military garrison -- another subject of ridicule by Hong Kong netizens.