Stoltenberg said it was regrettable that China had decided not to participate, local media reports.
Switzerland has invited around 160 countries to the event to discuss possible ways to achieve lasting peace in Ukraine.
China announced a week ago that it would not participate.
Foreign Ministry spokeswoman Mao Ning in Beijing stated that there is a significant disparity between the conference’s design and China’s expectations, as well as the general expectations of the international community.
Stoltenberg said China’s cancellation was not surprising.
He explained that not only did China fail to condemn the invasion, but President Xi Jinping and Russian President Vladimir Putin had signed an agreement just before it, promising each other an unlimited partnership.
Stoltenberg said that since the invasion, China has been selling advanced technology, microelectronics, and other equipment to bolster the Russian war economy, enabling Russia to continue the war against Ukraine.
Switzerland has confirmed that more than 80 countries will participate in the peace conference.
Russia, which invaded Ukraine more than two years ago, has not received an invitation.
