The legislation is "a naked interference in China's internal affairs", Wang told former US defense secretary William Cohen at a meeting in Beijing, China's foreign ministry said in a statement.

Wang said China would "never allow any attempts to damage Hong Kong's prosperity and stability or damage 'one country, two systems' to succeed".

US lawmakers on Wednesday overwhelmingly approved legislation that supports human rights and democracy in Hong Kong and also backs the territory's anti-China protesters, sending the measure opposed by Beijing to President Donald Trump.

The Hong Kong Human Rights and Democracy Act requires the president to annually review the city's favourable trade status and threatens to revoke it if the semi-autonomous territory's freedoms are quashed.

They also passed legislation banning sales of tear gas, rubber bullets and other equipment used by Hong Kong security forces in putting down the protests, which are now in their sixth month.

The White House has not threatened to veto the measure and Trump is expected to sign it, according to a source familiar with the matter.

After Congress passed the bill, China's foreign ministry warned the country was ready to "resolutely fight back" with unspecified measures.