Selling in shares of Apple's Taiwanese suppliers, which make many of the components found in iPhones and the Apple Watch, mostly outpaced the 1 percent decline in electronics subindex and the broader main index.
As of 0132 GMT, the main TAIEX index fell 0.7 percent, to 8,947.66, after closing up 0.3 percent in the previous session.
Shares of Taiwanese assembler of iPhones Hon Hai Precision  were off 1.1 percent, while those of rival and second assembler of iPhones Pegatron dropped a larger 2.9 percent.
Shares in chip supplier TSMC were off 1.1 percent and those in chip test and package supplier ASE were sliding a bigger 2.1 percent. The Taiwan dollar firmed T$0.224 to T$31.183 per U.S. dollar.