The Chinese government has never delayed releasing or withheld information about COVID-19, but instead has promptly informed the world about the situation and made great contributions to the global effort in battling this pandemic, officials said on Sunday.

Chinese scientists are willing to collaborate with international peers in finding the origin of the virus, creating new drugs and vaccines and jointly safeguarding international public health, they added.

Recently, some foreign media reported that the Chinese government withheld key genetic information about the novel coronavirus during the early days of the epidemic, resulting in the global pandemic. The reports also claimed China is the source of the virus and thus should be held accountable.

Ma Xiaowei, head of the National Health Commission, dismissed these allegations, saying they "completely disregard the facts".

"The truth is the Chinese government did not delay releasing or conceal information, but informed the international community about the virus and the situation at a moment's notice," he said, adding that these actions have "greatly contributed to the global efforts to control the pandemic".

As the pathogen that causes COVID-19 is a completely new virus, Ma said, its characteristics bear mysteries that require time and rigorous effort to solve. Despite the expanding evidence and insight into the pathogen, "humanity still has a very limited understanding", he said.

Ma said the Chinese Center for Disease Control and Prevention and other institutions had isolated the novel coronavirus on Jan 7. Two days later, China had passed the etiological evaluation to the World Health Organization. On Jan 12, China published the full genetic sequence of the virus for the world.

"The timeline has been clear and the work done by the Chinese government and scientists can stand the test of time," Ma said. "The virus knows no borders, the pandemic recognizes no ethnicities. It is a common challenge to all mankind, and solidarity and international collaboration are our most powerful tools against it."

Wang Zhigang, minister of science and technology, said China will keep its promise of providing COVID-19 vaccines as a global public good and make them accessible to the world after they have been proved safe and reliable.

Wang said China has one adenovirus vector vaccine and four inactivated vaccines in clinical trials. "China's overall vaccine development is on par with other countries, and for some vaccines, it is at the forefront of the world," he said.

"However, vaccine development is an extremely complicated and rigorous scientific undertaking. It is hard, and it takes time," he said, adding that there are also many great uncertainties surrounding the scientific research.

Wang stressed that safety, potency and accessibility are three priorities for vaccine development, and China will keep collaborating with other countries to achieve this undertaking.

As for the development of treatment, Wang said medicine is the most essential product in a patient's recovery, and China has over 160 institutions and companies researching drugs against COVID-19, with a total of 10 drugs and treatments being added into China's national diagnosis and treatment guidelines.

China has also made important scientific progress on chloroquine phosphate, favipiravir, carrimycin, tocilizumab, convalescent plasma and stem cell therapies, he said, adding that these drugs and treatments have played a key role in increasing the cure rate and reducing fatalities on the front lines.

Wang said Chinese scientists have shared their knowledge via published journals, online seminars, and in-person exchanges with peers from over 200 countries and regions.

Wang Xiaodong and Zhang Yangfei contributed to this story.