China has cautiously welcomed the signing of a landmark free-trade deal between the 12 Pacific rim nations.

The Trans-Pacific Partnership (TPP), led by the US, looks to cut trade tariffs and sets a common standard for the countries involved. The links between US and Japan are likely to be the biggest contributors to the deal.

China is not one of the 12 countries involved, but said it is "open to any mechanism" that follows the rules of the World Trade Organization (WTO).

The countries involved - Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, Vietnam and USA - have a combined population of around 800 million and are responsible for around 40% of the world's entire economy.

China's Ministry of Commerce described the TPP as "one of the key free trade agreements for the Asia-Pacific region".

"China hopes the TPP pact and other free trade arrangements in the region can boost each other and contribute to the Asia-Pacific's trade, investment and economic growth," it said.