China appears to have decided to stop accepting lists of prisoners whom foreign governments want released, a prominent human rights advocate said Friday.

John Kamm, a US businessman turned activist who has helped win clemency for numerous Chinese prisoners, predicted that Beijing may move to end its regular human rights dialogues with Western nations and Japan.

"I have been advised that a policy decision was made in mid-2012 to no longer accept prisoner lists on the margins of bilateral rights dialogues," said Kamm, founder of the Dui Hua Foundation.

"The days of submitting big lists of prisoners are probably over," Kamm said at the Center for Strategic and International Studies in Washington.

Kamm said that Beijing refused to take a list of prisoners during talks with the European Union last year and that a Chinese leader told a senior US official, '"No one will be released; we don't have to do that anymore.'"

But Kamm said that there may be "some flexibility" in enforcing the policy and that his own group -- which is non-governmental and stresses a respectful tone --remained in touch with Chinese officials on prisoners.

Kamm said that the shift may reflect growing Chinese confidence or could simply reflect decisions by individual policymakers in Beijing who found the tone on the issue "insulting."

Kamm appealed to China to release political and religious figures, saying that clemency "is not a sign of weakness, but a sign of confidence and strength."

Kamm noted that President Barack Obama's administration has won few concessions from China on human rights.

By contrast, China earlier freed prisoners to meet specific goals including ensuring the attendance of president George W. Bush and other leaders at the 2008 Beijing Olympics and winning normalized trade relations with the United States during Bill Clinton's presidency.

Kamm said that the release of prisoners paid dividends for China, which avoided lasting economic sanctions in the wake of its bloody 1989 crackdown on pro-democracy protests in Tiananmen Square.

"Had China lost access to the American market in the early 1990s, it is doubtful that the Chinese economic model would have taken place," Kamm said.