Hong Kong's Cardinal Joseph Zen Ze-kiun has received criticism from the state-sanctioned Chinese Catholic Patriotic Association after taking part in a pro-democracy rally in Hong Kong that coincides with a series of events to mark 10 years since the changeover.

Tens of thousands of demonstrators took to the streets of Hong Kong last Sunday to protest the lack of progress towards full democracy in the city.

Prior to the march, Cardinal Zen encouraged people to join in the march in order to voice their concerns over the deteriorating situation of marginalised people in the city, including those still living below the poverty line and those persecuted for defending human rights.

Liu Bainian, deputy head of the Chinese Catholic Patriotic Association, criticised Cardinal Zen's decision to join the rally.

"If all Catholics in Hong Kong followed suit [by demonstrating], how can Hong Kong achieve stability? If the Vatican supports someone like him [Zen], how can it win China's trust?" Liu was quoted as saying by the South China Morning Post.

In the last week, Pope Benedict XVI sent a reconciliatory letter to Chinese Catholics in which he appealed to China to respect religious freedom and said that the state-sanctioned church was "incompatible" with the Vatican's rule of appointing its own bishops.

Relations have remained distant between China and the Vatican for decades but took a particularly frost turn last year after two cardinals were appointed by the Chinese Catholic Church without Vatican permission.

The Chinese Government's persistent refusal to allow Vatican-appointed bishops on the mainland and the Vatican's continued links with Taiwan also remain as stumbling blocks to closer Sino-Vatican relations.