The UN says China has postponed a long-awaited inspection visit by its special rapporteur on torture which was due to have taken place in late June.
Falun Gong members are among those China is accused of abusing
Beijing says that it needs more time to prepare and that this should be read as a sign of just how much importance it attaches to the visit.
The move has been criticised by a human rights group which says it raises questions about Beijing's sincerity.
The rapporteur, Theo van Boven, has said he regrets the postponement.
The trip has been under discussion for almost a decade and Mr van Boven was finally due to make his first tour of China at the end of June.
"The need for additional time to prepare for the two-week visit, especially given the different authorities, departments and provinces involved, was cited by the government as a season for the postponement," Mr van Boven said in a statement.
Nicholas Becquelin, of Human Rights in China, told BBC News Online the postponement "does nothing to dispel the impression that China has something to hide".
In Mr van Boven's annual report, released in March, the section on China was the longest, with more than 130 cases of reported torture and abuse.
Mr Becquelin said the Chinese authorities' treatment of their citizens raised three main areas of concern:
The alleged use of torture to extract confessions from those in pre-trial detention.
The alleged torture of members of groups which Beijing considers a threat to national security or to its hold on organised religion. These include practitioners of Falun Gong, ethnic Uighurs in Xinjiang, members of underground churches
Extra-judicial detention, for example the use of "re-education through labour", which Chinese citizens can be sentenced to for up to four years without trial
The rapporteur has said he will only visit China if he can make unannounced visits to places of detention and have unsupervised interviews with prisoners.
"This is a risk the government is apparently not ready to handle," said Mr Becquelin.
Earlier attempts to organise a visit by the UN torture rapporteur have been hindered by disagreements with Beijing over the terms of reference.