China should aspire to be seen as a "moral inspiration" to the world as it takes its place as an international superpower, John Bercow said, in what appeared to be a veiled reference to Beijing's poor human rights record.

The Commons Speaker, who was introducing president Xi Jinping ahead of the Chinese leader's address to MPs and peers, said "the world will be watching" the Asian nation's progress.

Mr Bercow also pointedly referred to another world figure who had recently addressed both Houses of Parliament, Burma's Aung San Suu Kyi, who he described as a "democracy champion and international symbol of the innate human right of freedom".

The Speaker told Mr Xi: "Your country is engaged in an experience and an experiment without equal in history.

"You are attempting to complete an industrial revolution, which took Britain the better part of two centuries, in little more than two decades.

"Your country has seen a transformation in how its people work and in what they rightly expect for themselves, for their families and for their society.

"The enormous challenge of how to deal with this falls to you and to your colleagues.

"Yet what China does, economically but also politically, is seen by and relevant to not merely your own 1.5 billion citizens, it is seen by and relevant to billions more across the globe.

"The world will be watching and waiting expectantly on the outcome as the emerging superpower that is China takes its new place in the world.

"In this century, no country can exist in isolation. In all matters, from international law to individual liberty, we should all aspire to be seen not merely as a powerful force in the world but as a moral inspiration to it."

Addressing the audience in Parliament's Royal Gallery, Mr Bercow referred to "the wise Chinese words" that "it is better to light a candle than to curse the darkness".

"We very much hope that your time here will assist the process of illumination," he told Mr Xi.

The Speaker said both China and the Houses of Parliament were "both very ancient and truly modern".

"It is a reflection of our changing times that we have hosted no fewer than four prominent daughters and sons of Asia in our Parliament in the past three years, starting with Daw Aung San Suu Kyi of Burma, the Nobel peace prize winner, democracy champion and international symbol of the innate human right of freedom," he said.

The Speaker said there were "social and personal" links as well as "economic and political" ties between the UK and China.

"This trip should provide the means for both sides to come to understand one another better," he said.

Mr Bercow had earlier appeared to obliquely criticise China while intervening from the Speaker's chair in the House of Commons.

During a question comparing the UK's relationships with China and India ahead of Indian prime minister Narendra Modi's visit to the UK next month, Mr Bercow pointedly said: "And of course the Indian prime minister is the representative of a great democracy."

There were audible intakes of breath in the Commons after Mr Bercow's comment, which came just hours before Mr Xi's ceremonial visit.

Lord Speaker Baroness D'Souza told the president that offering an address to both Houses in the Royal Gallery was a "rare tribute, which we reserve only for those we hold in the highest regard".

The peer raised the issue of Hong Kong, quoting former Chancellor Lord Howe, who she said had been a "great friend of China".

"With specific regard to Hong Kong, he said that China's principle of one country, two systems was indicative of its leadership employing a wisdom that would lead us far into the future, not just in economic terms but in political and institutional ones as well," she said.

"It seems that that wisdom endures to this day."

Amnesty UK's director Kate Allen said: "It's welcome that the Speaker of the House of Commons made reference to international law, individual liberty and morality when he welcomed President Xi Jinping.

"Mr Bercow also mentioned the Nobel peace prize, a timely reminder that Chinese Nobel laureate Liu Xiaobo is still languishing in jail, serving an 11-year sentence simply for peacefully writing about proposed democratic reforms.

"This lavish red-carpet visit comes amid a worsening crackdown on human rights in China, and it's a matter of shame that there has been no mention of that from our government.

"David Cameron needs to follow the Speaker's example."