A senior UK diplomat has delivered a message from the new British Prime Minister Theresa May, saying her country supported China successfully hosting the upcoming G20 summit.

Alok Sharma, the newly-appointed minister in-charge of Asia in the UK Foreign Office, made the comments during a meeting with Foreign Minister Wang Yi on Monday in Beijing.

Sharma said he came to China to send an important message: that the UK paid great attention to cooperation between the two countries and regarded China as a significant global strategic partner.

Xi's successful visit to the UK last year was a milestone, Sharma said.

He also said that May had written a letter to Xi and Premier Li Keqiang to express her expectations for the G20 summit.

The UK supports China successfully hosting the summit and expects to enhance its cooperation with China on trade and the economy as well as on global issues, May said.

During their meeting, Wang said China was willing to work together with the UK to push forward the partnership between the two countries and further deepen practical cooperation in various fields.

He said the China-UK relationship had kept up a good momentum of development in recent years, and that President Xi Jinping's state visit to the UK last year had pushed bilateral ties to a new historical level.

He also asked Sharma to extend China's welcome to the new UK Prime Minister, ahead of her attendance at the G20 summit to be held in Hangzhou in September.

"China is willing to keep communication and negotiation with the UK in this regard and make sure that the summit is a success," Wang said.

Wang appreciates Sharma's visit to China at the beginning of the establishment of the new UK government, saying that he believes that the UK will continue to pursue an active and open policy towards China.

Stronger cooperation between China and the UK is in line with the fundamental interests of people from both countries, and is also conducive to world peace, stability and development, Wang added.