China has denounced remarks by Germany's EU commissioner that critics described as racist toward Chinese, saying the comments reflected a superiority complex held by "some Western politicians".

In a recent speech to businessmen in Hamburg, Guenther Oettinger, the senior member of Chancellor Angela Merkel's conservative party, used the derogatory term Schlitzaugen - slit eyes - to describe people from China and of other Asian descent.

China's foreign ministry spokeswoman said the comments were baffling.

"I think the relevant remarks actually reflect some western politicians' deep-rooted and baffling sense of superiority," the spokeswoman, Hua Chunying, told a regular press briefing.

"We hope these people can learn to objectively view themselves and others and learn mutual respect and equal treatment," Hua said.

Oettinger tried to play down his remarks, calling them "somewhat sloppy", but he did not apologise and defended himself against accusations of racism. He also made comments on gay marriage that some critics described as discriminatory.