Some of America's top technology trade groups have urged the US Congress to pass the US-Mexico-Canada Free Trade Agreement (USMCA) as soon as possible.

In an open letter, they argued any further stalling in adopting the legislation would stand in the way of modernising trade law to accommodate the digital economy.

However, they also warned Congress not to agree to any changes in the thresholds for duty-free shipments into the US that may be suggested by the Trump administration.

The letter was signed by the Internet Association and the Semiconductor Industry Association, among other key tech trade groups.

A replacement for the North American Free Trade Agreement, the USMCA was signed by leaders from the US, Mexico and Canada back in November 2018, but it must also be ratified by the three nations' lawmakers.

Mexico has already done this, but the American Congress has so far declined to based on concerns surrounding labour, the environment and pharmaceuticals.

However, negotiations with US Trade Representative Robert Lighthizer on proposed amendments are expected to resume this week, with the USMCA one of president Donald Trump's top priorities for the autumn period.

Treasury secretary Steven Mnuchin told Fox Business Network this week that passing it is at "the top of our agenda", something Mr Trump also said in his 2019 State of the Union address.

The trade groups are keen for swift action to approve the FTA, but have insisted that implementing language to change the de minimus threshold - the value below which imported goods are free of sales tax and duties - would undermine any broader gains, particularly for small businesses.

"Passing the USMCA would be a significant step not only towards guaranteeing the leadership of North America in the global digital economy, but also towards establishing a worldwide framework to address the challenges confronting global access and usage of digital trade," their letter concluded.

Earlier this year, there had been hopes the USMCA would be ratified by all three countries' governments before the Mexican legislative session ended on April 30th 2019, but this did not prove to be the case.