Ministers and officials from around the globe have begun key talks at the World Trade Organisation summit in Mexico.

The first day of talks in Cancun is likely to be dominated by finalising the summit's agenda and a poverty reduction initiative centred on cotton production which has been put forward by four developing countries.

Britain's 46-strong team, led by trade secretary Patricia Hewitt, has joined around 4,700 delegates from 146 countries.

Ahead of the talks, WTO director-general Supachai Panitchpakdi said Cancun would be an "important step" towards ensuring the Doha round of negotiations succeed.

"Trade liberalisation is an important engine of economic growth - it contributes to poverty alleviation. Trade liberalisation also leads to a more efficient allocation of resources, including natural resources," he said.

"There is great expectation about the results of the market access negotiations, and rightly so. There can be little doubt that the benefits from liberalisation could be substantial. The share of developing countries in world trade amounts to approximately 30 per cent.

"Through the new negotiations, it can be made to grow even further."

The summit will open with statements from senior leaders including United Nations secretary general Kofi Annan.

The key battleground is likely to be over agriculture subsidies which has massive political implications for both the US and EU.

Four general issues of widening trade opportunities, government procurement, competition and investment will form the basis of talks but officials say the best that can be expected is a lose framework to be agreed when the summit ends.

Mexico's president Vicente Fox, who as host will start the summit, has urged both the United States and Europe to cut aid to farmers.

Patricia Hewitt warned there would be serious consequences if governments do not make a deal.

"If we are to fail, and I don't believe we will, it would be disastrous. We would have failed to offer real prospects to move out of poverty to move millions of people," Hewitt said.

"We would have also done probably irreversible damage to the WTO."

As with past summits, anti-globalisation protestors have arrived in their thousands to call for the WTO to be broken up.

But Hewitt argued that the trade body could play a key role in "lifting millions out of poverty".

"Don't knock and try to destroy an organisation which is trying to bring the world together and support countries you want to help," she said.