Handlers were barring reporters in China from the hall during appearance of Tony Blair.
Reporters were allowed to listen to Blair's speech to the conference via a closed circuit television feed, but the transmission was cut after the former prime minister moved into a 40-minute discussion and question and answer session.
No explanation was given.
In his brief address, Blair urged governments to embrace globalization and band together to solve problems such as global warming and terrorism.
"We must win the hearts and minds," Blair said on fighting terrorism.
"Change is the hardest thing to do," he said in referring to the role of governments in preparing citizens for a more globalized economy.
Since retiring in May, Blair has held the sensitive role of special envoy representing the Quartet of Mideast mediators - the U.S., the European Union, the United Nations and Russia - helping the Palestinians lay the groundwork for a viable independent state alongside Israel.
His trip also comes just months ahead of an expected state visit to China by his successor, Gordon Brown.
During his term as prime minister beginning in 1997, Blair was frequently criticized in the British media for attempting to manipulate media coverage.