British Prime Minister David Cameron heads to China on Sunday aiming to reset relations with Beijing after a row over his decision to meet the Dalai Lama.

Cameron's trip is aimed at fostering ties with the new leadership of President Xi Jinping and boosting trade, with more than 100 business people set to accompany him.

Human rights groups have urged Cameron to press China on promised reforms.

Relations between Britain and China have been frosty since Cameron met Tibet's exiled spiritual leader the Dalai Lama in May 2012.

But aides said that the trip was a chance to "turn the page" in the relationship with Beijing and that Cameron wanted the visit to be "forward-looking".

Cameron sent his first message in Mandarin on Sina Weibo, China's version of Twitter, this week and now has more than 101,000 followers.

"Hello my friends in China. I'm pleased to have joined Weibo and look forward to visiting China very soon," he wrote in the message.

But Cameron faced accusations of double standards after he used a visit to the Commonwealth summit in Sri Lanka last month to urge Colombo to address war crimes allegations.

"Given the deplorable state of rights in China, Cameron should pick up where he left off earlier this month in Sri Lanka, when he said he would 'shine a global spotlight' on abuses," said Brad Adams, Asia director at Human Rights Watch.

"The UK should have a consistent approach to human rights, which must include a forceful public condemnation of rights violations that can be heard by the people of China as well as the government."

The Free Tibet group said that Cameron "should speak up" for Tibetans.

Cameron's meeting with the Dalai Lama two years ago prompted fury from Beijing, which branded it an "affront to the Chinese people".

But the British premier said in parliament in May this year that London does not support Tibetan independence and that he had "no plans" to meet the Dalai Lama.

Cameron last visited China in November 2010 and this will be his first trip there since Xi took office in March.

The trip is regarded as so crucial that the annual Autumn Statement budget update by finance minister George Osborne has being postponed by one day to December 5.

Osborne visited China in October, coming away with a range of investment deals as Britain seeks to tame its record deficit.

Britain also in October signed a £16-billion ($26-billion, 18.9-billion-euro) deal involving Chinese nuclear firms CGN and CNNC to build Britain's first nuclear plant in a generation, along with French energy giant EDF.

The business leaders reportedly accompanying Cameron will include the bosses of Jaguar Land Rover, the English Premier League, Royal Dutch Shell, the London Stock Exchange and GlaxoSmithKline.

Cameron said when he announced the visit earlier this month that he wanted to "forge a relationship that will benefit both our countries and bring real rewards for our peoples".

He added that the visit was aimed at "opening the way for British companies to benefit from China’s vast and varied markets and preparing the way for a new level of Chinese investment into the UK".

The Conservative leader has often spoken of the need for Britain to compete in the "global race" against rising economic powers.