The Nobel Peace Prize committee is tightening security to prevent eavesdroppers on decisions that can infuriate the powerful, Reuters reported.

"We have taken certain precautions," Geir Lundestad, the head of the Norwegian Nobel Institute, told Reuters in his office in central Oslo.

The winner has already been chosen from about 230 candidates, but his or her name will remain secret until the formal 2012 award on October 12.

"Leaks in general have not been a problem. But we want to protect that record."

One fear is of lip-readers, perhaps using telescopes from nearby buildings. "You just pull down the curtains and there are no lips to read," Lundestad said.

"Cellphones are terrible from a security point of view ... We never bring cellphones into the room because they give experts easy access," he added. Phones can be activated remotely and used as listening devices.

The committee had taken advice from security consultants on other measures Lundestad declined to discuss.