The official Vatican missionary news agency Fides said Li Qinghua, 31, was being held in a prison cell where he is monitored by concealed cameras while prostitutes hired by the government try every means to seduce him.

Carrie Gracie reports from Beijing on China's response

But China has questioned the accuracy of the Vatican's comments. A Foreign Ministry spokesman said the reports from Rome had not been confirmed.

An official in China's provincial religious affairs bureau said the matter would be investigated.

Reverend Li is being held in the northern Xushui region on suspicion that he contacted other priests from the underground Roman Catholic Church, which is banned in China because of its loyalty to Rome, the Vatican said.

It said the aim of the seduction was to get compromising photographs to blackmail the priests into revealing secrets about the underground church.

Police arrested the priest in the town of Guan in Hebei province in northern China, it added.

'Continual pressure'

The Vatican said its information came from other priests who had been incarcerated in the same prison.

"These women ... try at all costs to have sexual relations with you, talking in tender tones, accompanied by movements to make you succumb to temptation," a witness told Fides.

"Sometimes police and prostitutes will take the priests to discotheques to make them fall gradually into their arms."

The agency said the "pressure placed on the priests is continual; even if they resist, they receive constant visits from girls trying to embrace them".

"If you hesitate for a moment to repulse them ... the picture taken by the camera gives the impression that you have been sleeping with them," the witness said.

Priests who continue to resist the sexual torture are sent to labour camps to be "re-educated" or are sent back to the police stations where they were arrested, Fides said.

Church split in two

China's underground church remains loyal to the Vatican and rejects the state-approved Catholic Church, autonomous from Rome, that was set up by the government in the 1950s.

Many clerics and adherents of the underground church have been imprisoned for refusing to defect to the official Catholic Church.

The director of Fides, Reverend Bernardo Cervellera, said Chinese authorities are targeting the underground church in Hebei province because that is where it is strongest.

Beijing has not had diplomatic ties with the Vatican since 1957, because the latter recognises Taiwan.

Beijing refused to allow Chinese Catholic Bishops to travel to Rome last year to attend the Asian synod called by the Pope.