"The international trade in Burmese gems helps finance repression and puts millions into the pockets of Burma's abusive rulers," said Arvind Ganesan, director of the New York-based rights group's business and human rights programme.
US President George W Bush on Tuesday signed the legislation into law to tighten an existing ban on the trade in gems from Burma.
"With the new law, US retailers can no longer legally profit from the trade in Burmese rubies and jade," Ganesan said in a statement.
As part of its economic sanctions on Burma's military regime, the US government has prohibited private investment in the country since the early 1990s and banned the import of Burma goods since 2003.
Despite the 2003 trade ban, a loophole permitted the purchase of gems that originated in Burma but were cut or polished in third countries, such as India or Thailand. The new legislation closes that loophole.
Precious stones such as rubies and jade, are Bujrma's third most important export item, earning the country about 647 million dollars in the fiscal year 2007-08, which ended March 30, Human Rights Watch said.
The European Union and Canada already prohibit the import of Myanmar gems.
The change in the US law would stipulate that retailers keep records documenting the origin of rubies and jade to prove they are not from Burma.
The law, which would go into effect 60 days after Bush signs it, applies to finished jewelry.
Burma has been ruled by military regimes since 1962 when General Ne Win staged a coup against elected Prime Minister U Nu and launched the country along his economically disastrous "Burmese Way to Socialism."
Burma dropped its socialist system in 1988 in the aftermath of countrywide demonstrations against decades of military misrule and opened the country up to foreign investment and trade.
But the regime's atrocious human rights record, starting with a bloodbath in 1988 to end the protests, has earned it pariah status among Western democracies, which have slapped increasingly onerous economic sanctions on the country during the past two decades.//DPA - July 29, 2008