US Secretary of State John Kerry on Monday urged China to free Nobel Peace Prize winner Liu Xiaobo as the writer and activist marked five years in detention.

On the eve of the latest Nobel Peace Prize ceremony in Norway, Kerry also urged China to release Liu's wife Liu Xia from house arrest and voiced concern over Beijing's clampdown on other activists including anti-corruption campaigner Xu Zhiyong.

"We strongly urge Chinese authorities to release Liu Xiaobo, to end Liu Xia's house arrest and to guarantee to Liu Xiaobo and his family members all internationally recognized human rights protections and freedoms," Kerry said in a statement.

While calling for a "constructive relationship" with the Asian power, Kerry said: "We continue to believe that respect for international human rights is critical to China's growth, prosperity, and long-term stability.

Liu was detained in 2008 after spearheading Charter 08, a bold petition for greater protection of human rights in the communist country. The following year, he was handed an 11-year sentence for subversion.

China voiced outrage over the Nobel committee's decision to grant the prestigious prize to Liu, with authorities trying to block out the news and putting his wife under house arrest.

Liu's supporters have voiced fear that pressure will gradually ease on China to free Liu as time passes and the spotlight fades.

A lawyer for the Nobel laureate said last month that he will appeal the conviction. In a rare statement, Liu Xia in June appealed to President Xi Jinping to choose "justice" over "merciless oppression."