The UN has dropped the 31 January deadline by which time all countries were expected to officially state their emission reduction targets or list the actions they planned to take to counter climate change.

Yvo de Boer, UN climate change chief, today changed the original date set at last month's fractious Copenhagen climate summit, saying that it was now a "soft" deadline, which countries could sign up to when they chose. "I do not expect everyone to meet the deadline. Countries are not being asked if they want to adhere… but to indicate if they want to be associated [with the Copenhagen accord].

"I see the accord as a living document that tracks actions that countries want to take," he told journalists in Bonn.

"It's a soft deadline. Countries are not being asked to sign the accord to take on legally binding targets, only to indicate their intention," he said.

The deadline was intended to be the first test of the "Copenhagen accord", the weak, three-page document that emerged at the end of the summit, and which fell far short of original expectations. It seeks to bind all countries to a goal of limiting warming to no more than 2C above pre-industrial times and proposes that $100bn a year be provided for poor countries to reduce emissions and adapt to climate change after 2020.

But with just 10 days to go, only 20 countries out of 192 have signed up, with many clearly unready or unwilling to put their name to the document. Countries which have signed so far include India, Russia, Mexico, Australia, France and Norway.

De Boer also endorsed the controversial idea of short-circuiting the traditional UN negotiating process of reaching agreement between all countries by consensus. Instead, he argued that a smaller group of countries could negotiate a climate agreement on behalf of the many.

"You cannot have 192 countries involved in discussing all the details. You cannot have all countries all of the time in one room. You do have to safeguard transparency by allowing countries to decide if they want to be represented by others, and that if a debate is advanced then the conclusion is brought back to the larger community", he said.

However, this more exclusive method of reaching agreement was criticised by some in Copenhagen after the host government, Denmark, convened a meeting of 26 world leaders in the last two days of the conference to try to reach agreement on behalf of everyone.

Critics argued that this was not only illegal, but undermined negotiations already taking place among the 192 countries and threatened the UN's multilateral and democratic process.

"The selected leaders were given a draft document that mainly represented the developed countries' positions, thereby marginalising the developing countries' views tabled at the two-year negotiations. The attempt by the Danish presidency to override the legitimate multilateral process was the reason why Copenhagen will be considered a disaster," said Martin Khor, director of the South Centre, an intergovernmental think tank for developing countries based in Geneva.

The US and Britain have argued since the conference that climate negotiations are best served by meetings of the world's largest polluters, such as China, the US, India, Brazil and South Africa. These countries, which emit more than 80% of global emissions, signed up to a deal in the final hours of the summit.

Brazil, India, China and South Africa, known as the "BASIC" group, meet next week in Delhi to agree a common position ahead of further UN climate talks.