US House of Representatives speaker Nancy Pelosi said Tuesday that the fight against climate change was a "game changer" in China-US relations, as she visited Beijing on a trip focused on energy.

Pelosi, a tough critic of China's human rights record and a vocal advocate of environmental protection, is leading a delegation from the US Congress to China on a working visit devoted to energy and climate change.

"I think that this climate change crisis is a game changer in US-China relations, it is an opportunity that we cannot miss," she said at a clean energy forum in Beijing.

Delivering a speech at the meeting, which aims to find ways for the United States and China to cooperate on clean energy, Pelosi linked the issue of human rights to environmental justice.

"We see the thread of workers' rights, human rights, people's rights, and environmental justice -- a principle that must be upheld as we go forward," she said.

The House's first female speaker also called for the protection of copyright in the two nations' quest for clean energy.

"If we are going to invest in the technologies -- and we must -- we must have respect for intellectual property rights," she said.

Pelosi arrived in Shanghai on Sunday with the delegation where she visited one of China's most influential Catholic priests and toured the financial district.

Her visit comes just over a week before the 20th anniversary of the 1989 bloody government crackdown on pro-democracy protesters in and around Tiananmen Square.

But like US Secretary of State Hillary Clinton, who visited China in February, Pelosi has not yet made any public statements about human rights.

She is due to visit Tianjin, a city near Beijing, and meet top Chinese leaders before she leaves on Sunday.