World Trade Organization member states on Thursday urged China to make its trade policies more transparent amid a "striking" lack of clarity on its rules.

China, which recently become the largest trader in the 160-member group, has failed to live up to key transparency commitments it made when it joined the organisation in 2001, WTO members said during a three-day policy review.

The WTO Secretariat, which has drawn up a 200-page report on China's trade policy over the past two years, acknowledged it had not been able to obtain key documents from Beijing since they had not been centralised and many had not been translated into one of the group's official languages.

Malaysian ambassador Mariam Salleh, who chaired the mandatory biannual review, said members had stressed "the increased responsibility that comes with becoming a lead player in the multilateral trading system".

One source said a full overview of the country's complex web of national and sub-national trade laws and regulations was effectively impossible, while EU ambassador Angelos Pangratis described the lack of clarity on trade issues as "striking".

Canada's representative also criticised the "often vague and insufficent information available publicly".

China has been locked in disputes with several members of the WTO over its trade policy, which other members say is often unclear and even contradictory.

In May, the WTO rejected Chinese tariffs on US-made luxury cars, handing Washington a victory on one of the growing number of disputes between the world's two largest economies.

US representative Chris Wilson criticised China's "apparently retaliatory conduct" in its use of duties, and said the country appeared to ignore a number of WTO findings against it.

Chinese Assistant Minister of Commerce, Wang Shouwen, flatly rejected the allegations as "baseless", and insisted that China "has one of the best track records of implementing WTO rulings".

Many of the 50 WTO members who took part in the review also criticised Beijing's use of export restraints and taxes, restrictions on foreign investments and said it must improve protection for intellectual property rights (IPR).

"An enormous amount of work remains if China is to close significant loopholes in its legal framework and reduce the unacceptably high (IPR) infringement levels," said the US's Wilson.

But Shouwen stressed Thursday that his country had made great strides to address these issues and pledged to do more to improve transparency.

The country's ranking as the world's biggest trader and second-largest economy "cannot hide the fact that China is still a developing country," he added.