Chinese exports have become more profitable in the 18 months since the revaluation of its currency, the renminbi, as industry has lifted productivity and moved into a growing range of higher-value products.

The rise in profits and volumes of exports comes despite an appreciation of about 6.5 per cent of the renminbi against the US dollar since mid-2005, and sharply higher prices for most raw materials.

The margins for textiles, electronics and machinery goods, which together account for 60 per cent of exports, all increased last year compared to 2005, according to figures compiled by Deutsche Bank.

The ongoing competitiveness of China also underlines how any focus by the US in trade talks on the currency alone will not be effective in rebalancing bilateral economic ties.

The new figures show margins rising even in the textile industry, albeit slightly, from 3.5 to 3.6 per cent in 2006. The sector has long been the most overcrowded and under pressure from currency appreciation.

The figures confirm recent studies by UBS and the World Bank showing that China is exporting a wider range of goods than a decade ago and at higher prices in the past two years.

China's export sector is experiencing a rapid structural upgrading in areas including technology, product mix and marketing. Most visibly, many textile, machinery and auto parts companies have dramatically expanded their product categories, enhancing their pricing power and profit margins.

Combined with investment in new technology, the dominance by Chinese companies of some industries may also be giving them more pricing power than previously thought.

The fastest growing export sectors in 2006 were aircraft parts, shipbuilding, integrated circuits, cars and car parts, electrical machinery and telecommunications equipment.