LOS CABOS  - US Secretary of State Hillary Clinton on Saturday entered a weekend of talks of the Group of 20 major economies in Mexico where her aides said she would push for freer but fairer trade.

Clinton started her three days in the Pacific Ocean resort of Los Cabos by heading to a private dinner with her counterpart, Foreign Secretary Patricia Espinosa. The setting for the G20 talks is deliberately informal, with Mexico hoping to foster cooperation rather than make concrete achievements.

Echoing frequent themes for President Barack Obama's administration, Clinton will call on major economies to tackle "21st century" barriers to trade and adhere to global standards, a US official said on condition of anonymity.

"In the 21st century, a lot of the barriers to trade, a lot of the distortions to trade, are not the ones that we're focused on largely in the 20th century, which were at the border," the official said.

He pointed to "anti-competitive government practices or distortions" which create obstacles on the market.

"So we're not saying we're forcing you or encouraging you to play by rules that we come up with, that we dictate. What we're simply saying is that there are global rules," the official said.

"These global rules and norms have been established for years, and it's very important for players in the global system to play by global rules and adhere to global norms," he said.

The US administration used a similar argument this week during a visit by China's vice president and likely next leader Xi Jinping, with Obama telling him that the rising Asian power should play by the "same rules of the road."

The United States accuses China of unfair trade practices such as an artificially low currency and weak protections for intellectual property rights. Xi promised to look at investors' concerns.

The official traveling with Clinton said that she would also speak to her counterparts on climate change. Clinton on Thursday announced a coalition which includes Mexico to cut short-term pollutants amid faltering global efforts to curb carbon dioxide emissions, considered the top cause of rising temperatures.

Mexico in 2010 helped breathe new life into UN-backed negotiations on a new climate treaty, but progress has been painstakingly slow and political support on fighting the problem has ebbed in a number of countries including the United States.

The weekend talks will prepare for a summit in June in Los Cabos of the Group of 20, a club of major rich and developing nations first established in 2008 to address the global economic crisis.

Twenty-eight nations are expected to take part in this weekend's talks, along with representatives of the European Union and African Union, US officials said. Clinton plans to meet separately with Australian Foreign Minister Kevin Rudd.