The US Congress has given final approval to a bill to restore normal trade ties with Vietnam.

The bill granting "permanent normal trade relations" (PNTR) status to Vietnam sailed through the Senate as part of an omnibus measure that was approved 79-9 during an all-night session.

The US House of Representatives voted for it 212-184 late Friday.

United States Trade Representative Susan Schwab said she was pleased at the passage of the "critical" legislation.

The measure would "afford the United States access to Vietnam’s fast growing market and launch a new era in the relationship between our two countries," she said.

The US Chamber of Commerce likened the passage of the package of trade bills, including the one on Vietnam, as an early Christmas present for American companies and workers expected to benefit from enhanced trade.

"Legislators have a chance to give American workers, companies, and consumers an early Christmas present," said Bruce Josten, the US Chamber's executive vice president for government affairs.

"This trade package is squarely in America's national economic interest," he said.