"What we are very concerned about is that anybody detained over the past few days is at high risk of torture or ill treatment and we need some independent scrutiny," he said, speaking from Hong Kong.
On Wednesday reports from the Tibetan capital said Chinese security forces were conducting house to house searches searching for activisits they believed had been behind the unrest.
Allison said Amnesty was also calling on China to allow an independent United Nations investigation into the situation in Tibet and the events of the past week.
Tibet's exiled spiritual leader, the Dalai Lama, has also called for independent investigators to be allowed into the region.
On Tuesday New York-based Human Rights Watch said it too was worried about the fate of Tibetans detained by Chinese authorities.
"Given the long and well-documented history of torture of political activists by China's security forces, there is every reason to fear for the safety of those recently detained," Brad Adams, the group's Asia director, said in a statement
Amnesty's Mark Allison said it was ironic that China had imposed a complete media blackout on the situation in Tibet at a time when authorities had promised complete media freedom in the run up to the Olympics.
"The crackdown clearly is not the kind of image China wanted to promote to the outside world, he said
China, Allison said, was "on notice from the international community" that it could not use methods it has used in the past against Tibetan protesters, such as torture and arbitrary detentions.