International Olympic Committee press chief Kevan Gosper says the media should have been told they would not have total internet freedom before arriving for the Beijing Olympics.
Gosper says both he and the international media had been taken by surprise that some sensitive websites had been blocked.
He says learning of it at almost the last minute is destabilising the international media.
Rights watchdog Amnesty International, whose website is among those barred in China, has condemned internet restrictions during the Games as "compromising fundamental human rights and betraying the Olympic values".
Organisers have also become involved in another media spat, over a South Korean television station's broadcast of a dress rehearsal for the Olympics opening ceremony, traditionally kept under wraps by Games organisers, that has infuriated Chinese internet users.
But the network says it took the footage legitimately.