There are thought to be around 10 million Catholics in China, the majority of whom worship in government-approved churches.

But many others do so in secret, in so-called "underground churches", which means the worshippers are often under surveillance and so never totally safe.

"They can be arrested ... Not many [priests] are detained. Maybe two bishops and maybe a dozen priests. They don't want to have martyrs ... They have more improved methods to destroy the church. Like threats, like enticement ... blackmail ... The Communists are the law, they can do anything," says former Bishop of Hong Kong, Cardinal Joseph Zen.

Despite the danger, they see themselves as the true followers of the Catholic Church.

Practically you are giving the power in the hands of the government ... What do they [the Communist Party] know about the qualities required to be a bishop?

Cardinal Joseph Zen

In the official church, the pope's authority is not recognised, but that may be about to change.

The Vatican and Communist Party appear to be close to making a historic deal, which would give Pope Francis a say in the appointment of bishops to China's official church.

In exchange, the Vatican would recognise bishops ordained without the pope's approval. In effect, a recognition by the pontiff that the two churches should become one.

The rapprochement between China's Communist Party and the Vatican is highly significant. China broke off diplomatic relations with the Vatican almost 70 years ago, following the Communist Party revolution led by Chairman Mao. 

Now, two of the world's most secretive organisations are close to announcing a deal that will decide the future of China's Catholics.

But the agreement has many detractors. One prominent critic, former Bishop of Hong Kong Cardinal Zenhas called it a betrayal, evil and a sellout.

"How can you legitimise a schismatic church ... they are completely under the guidance of the government. The church doesn't change just because you legitimise all the bishops ... If all the bishops, or the majority of the bishops, are the slaves of the Communist regime, there is no improvement," says Cardinal Zen.

He has never recognised the Chinese government's efforts to interfere in the church and therefore he travelled to the Vatican to warn the pope, face to face against any deal.

"I said to him [the pope] "this is fake". Last word is not enough ... Practically you are giving the power in the hands of the government ... What do they [the Communist Party] know about the qualities required to be a bishop?" says Zen.

"We're facing a disaster [if the Vatican establishes a representatives office in Beijing]. In the official church, those bad elements, those who really have no faith, that are just on the side of the government for their interest, those people now are happy ... they are being rewarded. The good people in the open church must be very disappointed ... They were waiting for the Holy See [Vatican] to give them courage. But the Holy See always encourages surrender, everywhere. Now, they give up their hope. With no agreement, there can still be hope for change. But now, it's the legitimatisation of the wrong situation ... Many people in the universal church may lose their faith in the pope."

Cardinal Zen talks to Al Jazeera about the challenges facing China's Catholics, the Vatican-China deal on appointing bishops, and his meeting with Pope Francis.

Source: Al Jazeera News