Companies exporting to the US could face increasing delays at the border as the government moves to tighten checks on imports.
The American government wants goods coming in to face more stringent reviews, with a particular focus on ecommerce and marketplace items.
This reflects the growing tensions between the US and China and political pressure from president Donald Trump, but also an enormous increase in mail imports over the past year.
Indeed, according to the US Customs & Border Protection agency (CBP), shipments increased from 1.4 million a day at the start of 2018 to around 2.1 million a day in August, with fears this could rise further to 2.5 million.
Resources are already stretched due to tariffs having been imposed on a number of commodities from China, so it is likely that any further customs checks in America could cause serious delays in shipping times.
Last week, the US Senate sent legislation to the White House decreeing that the US Postal Service must send advance electronic notifications related to every incoming international shipment to CBP.
In addition, the same bill requires that as of December 31st 2018, data on 70 per cent of all international mail must be transmitted before the goods reach the US border.
CBP insiders have previously said they would like to see better protection against illegal shipments through automation and data transfer as opposed to bringing in more physical inspections.