Chinese threats targeting Taiwan are unacceptable, a visiting German lawmaker on Monday told Taiwanese President Tsai Ing-wen in Taipei.

Klaus-Peter Willsch drew a parallel to Russia's invasion of Ukraine in comments to Tsai as she received German lawmakers from the Berlin-Taipei parliamentary friendship group in the German Bundestag.

"In Europe, we have been experiencing a big neighbor invading a small neighbor and trying to impose its will with military force since Feb. 24," Willsch said.

"We do not consider it acceptable that you are threatened by a neighbor with military force, to be forced into an unwanted cooperation. The German Bundestag is clear in its rejection of that," Willsch said.

Willsch and five German parliamentary colleagues arrived in Taipei on Sunday. Shortly after, Beijing protested the visit and urged German lawmakers to abide by the so-called One China Principle.

"We have taken note that not everyone likes that we are here this week, but we don't care. The German parliament decides itself about its relations with friendly parliaments, and cooperation with Taiwan is an important part of that and will remain so," Willsch told Tsai.

Tsai cited the expansion of authoritarianism globally and said all democracies should work together to jointly defend their values.

She said Taiwan and Germany have collaborated in many fields, such as energy transition, financial supervision and transitional justice.

The cross-party group is expected to stay in Taiwan until Thursday to exchange views with officials, lawmakers, think tanks focusing on security and high-tech business firms.