According to media reports, the climate document is the only unresolved issue in the statements the world leaders are expected to sign at the June 6-8 G8 summit.
But in Washington, Dana Perino, the White House spokeswoman, played down the document while acknowledging differences in the talks.
“By no means is there a final document,” she told the AFP news agency.
“We believe that there are many different approaches to climate change.”
She would not comment “on ongoing discussions”.
Fighting climate change
Representatives from the world’s leading industrial nations have met the past two days in the German town of Heiligendamm, where the summit is to be held, to negotiate over the proposed climate statement by Angela Merkel, the German chancellor.
On Thursday, Merkel addressed the German parliament over her proposals for tackling climate change.
“The leading industrial countries must move ahead on this question, otherwise we will not be able to fight climate change”
She said: “The leading industrial countries must move ahead on this question, otherwise we will not be able to fight climate change.”
The German proposals call for limiting the worldwide temperature rise this century to 3.6 F and aims to cut global greenhouse gas emissions to 50 per cent below 1990 levels by 2050.
On Saturday, Sigmar Gabriel, the German environment minister, criticised US policy on climate change, saying it stood in the way of an agreement at the summit despite that fact that many people in the US wanted a new approach to meet the concerns over climate change.
He said: “Unfortunately the government in Washington is obstructing this movement.
“For this reason it is going to be difficult to achieve success at Heiligendamm.”
Meanwhile, German authorities have taken measures to insure against violent protest at the summit meeting.
In recent weeks, authorities have erected a fence topped with barbed wire around the summit site, raided offices of various groups and taken body-scent samples to track potential offenders.
The extent of the measures taken by the German authorities has drawn criticism from a number of groups.
Previous G-8 summits have seen violent protest, particularly at Genoa in 2001 when police and protesters clashed in the streets for days.
Over the last few years the annual G8 summit has taken a greater interest in a number of the issues raised by protesters, such as aid to Africa, debt forgiveness for poor countries and the environment.