European Union foreign policy chief Catherine Ashton voiced concern about the "deterioration" of the plight of human rights campaigners in China after two more activists were jailed last week.

Ashton "regrets the decisions taken in late December to sentence the Chinese human rights activists Chen Wei and Chen Xi to nine and 10 years in prison respectively," her office said in a statement.

The EU's chief diplomat noted that the sentences followed the jailing of human rights lawyer Gao Zhisheng for three years.

Ashton also remains "particularly concerned about the case of human rights defender Ni Yulan, particularly in view of Mrs Ni's poor health," the statement said.

"The European Union is preoccupied with the deterioration of the situation for human rights activists in China and will continue to follow these cases attentively."

A court in the southwestern province of Guizhou said last week that it had jailed veteran activist Chen Xi for 10 years for subversion, one of the longest sentences yet to be handed down in a crackdown on dissent in 2011.

Chen Xi, 57, was involved in the 1989 Tiananmen democracy protest movement.

Days earlier, fellow veteran democracy activist Chen Wei, 42, who is not believed to be related to Chen Xi, was sentenced to nine years for subversion in the southwestern province of Sichuan.