Supporters of sweeping US legislation to fight climate change ramped up their push for a "green energy revolution" Wednesday with a vote on the massive bill expected at week's end.

"We are going to create a green energy revolution -- not only for our country but for the entire world," Democratic Representative Ed Markey, one of the measure's lead authors, said with a vote due as early as Friday.

The lawmaker from Massachusetts was speaking at a press conference outside the Capitol building with other supporters of the 1,200-page bill -- labor unions, environmental and religious groups, and some business leaders.

The legislation's backers have said they want to make as much progress as possible on the issue before December global climate change talks in Copenhagen, saying US leadership is key to forging an international accord.

"The whole world is looking at our capital. The whole world is waiting to see whether or not President Obama can arrive in Copenhagen as leader of the attempt to reduce greenhouse gases while at the same time unleashing a clean energy job revolution in our country and on our planet," said Markey.

Speaker of the House of Representatives Nancy Pelosi described the legislation as "a bill that unifies our country and our industry."

But while the legislation is chiefly backed by Barack Obama's Democrats, the president's Republican critics -- in the minority in the House and Senate -- have vowed to oppose it.

"The American Clean Energy and Security Act" aims to reduce greenhouse gas emissions 17 percent from 2005 levels by 2020, while creating "green" jobs.

It would create a "cap-and-trade" system limiting overall pollution from large industrial sources and then allocating and selling pollution permits.

But Republicans have charged that the effect will be to increase energy costs for consumers already struggling with a paralyzing recession and put Americans in some industrial sectors out of work.

"The 'cap and trade' bill will impose a national energy tax," said number two House Republican Eric Cantor, who charged the legislation "goes in the wrong direction."

The Senate is not expected to produce its version of the legislation before mid-September, and rival bills in the two chambers would need to first be reconciled before a final measure can be sent to Obama to sign into law.

"The goal of this legislation is to make our country safer so that we don't have to be so dependent on foreign sources of energy," said Democratic Representative Henry Waxman, chairman of the House Energy and Commerce Committee.

"We want to produce millions of new jobs and transform our economy as we reduce the carbon emissions that are a threat to the environment and our planet," said Waxman.

Pelosi said the bill's backers were aiming to get it to the floor of the House for a vote on Friday.