China has lodged solemn representations with the US over Taiwan leader Tsai Ing-wen's planned transit through its territory to and from three Pacific island nations, a spokesperson said on October 27.

Tsai reportedly departs on October 28 on a week-long trip to three states Taiwan has official relations with - Tuvalu, the Solomon Islands and the Marshall Islands - by transiting via Honolulu and Guam.

China has long opposed Taiwan forming diplomatic relations with other countries, as Taiwan is part of Chinese territory.

"The one-China principle is the common consensus of the international community and the principle to adhere to when dealing with Taiwan's external exchanges," Foreign Ministry spokesperson Geng Shuang said at a regular news briefing.

"As for the Taiwan leader's transit via the US, her real purpose is self-evident," Geng said.

China hopes the US will honor its commitment to the one-China policy and the three Sino-US joint communiques, not to allow Tsai's transit or send any wrong message to the pro-Taiwan independence forces, Geng said.

The spokesperson said the US should work to maintain the big picture of bilateral relations and peace and stability across the Taiwan Straits.