A widening political scandal is threatening to split Taiwan's ruling party and potentially set back efforts to build closer economic ties with China.

Recent allegations of influence-peddling by Taiwanese politicians, driven in part by investigators' wiretaps of one lawmaker's cellphone conversations, have stirred fear and paranoia among some political leaders.

"I'm sorry. It's not safe to talk right now. We are being monitored," said one political adviser within the Nationalist Party, whose leaders have both driven the investigation and have been the ones most damaged by it.