China has blasted British Foreign Secretary Dominic Raab for his remarks on Hong Kong in the House of Commons on Thursday.

"We express grave concern and firm opposition to the British government official once again making irresponsible remarks on Hong Kong," said a spokesperson of the Chinese embassy in the UK.

In response to a question, Raab told British lawmakers: "I remain seriously concerned by the situation in Hong Kong... We expect China to live up to its obligations under the Chinese-British joint declaration and… to its wider international human rights law obligations, including those in the UN charter."

The spokesperson said the embassy has made China's "solemn" position on Hong Kong clear to the UK government on many occasions.

"I want to stress that since Hong Kong's return, 'One Country, Two Systems' has achieved remarkable success in Hong Kong, which is widely recognized by the international community," the diplomat said.

Earlier this year, Chinese Ambassador to the UK Liu Xiaoming held two press conferences to explain the situation in Hong Kong and urge foreign sources to stop interfering in Hong Kong's affairs.

The embassy reiterated that the UK should immediately stop interfering in Hong Kong affairs and other internal affairs of China.

"The colonial era is long gone and Hong Kong is now a Special Administrative Region of the People's Republic of China. The UK has no sovereignty, no right to govern or supervise over Hong Kong. Hong Kong affairs are purely internal affairs of China," the embassy said.