Lorry drivers crossing the Channel will continue to need a recent negative Covid test result "until further notice", the UK government has said.
Hauliers have been required to prove they have tested negative since the border with France reopened last month.
The decision to continue testing comes from the French government, the Department for Transport said.
Transport Secretary Grant Shapps urged "all hauliers to get tested before getting to the border".
The decision comes as the introduction of new trading rules between the UK and European Union prompts disruption for some businesses and hauliers.
Mr Shapps said the government was "offering support to businesses to set-up testing facilities at their own premises, assisting the smooth passage of trucks and good across the border, as well as setting up testing at information and advice sites around the country".
Drivers and crew of heavy goods vehicles (HGVs), drivers of large goods vehicles (LGVs) and van drivers are advised to obtain a negative test before arriving in Kent or at other Channel crossing points.
There are now 34 testing sites for hauliers situated in key "stopping spots" across the UK, with further sites being set up, the DfT said.
Tests must be authorised and taken 72 hours before entry into France.
In addition to a negative Covid test result, some hauliers require a new 24-hour permit to enter Kent since the introduction of the new UK-EU rules.
France reported 21,703 new coronavirus cases on Thursday, while the UK reported 52,618.
Last month, the border crisis saw France refuse arrivals from the UK for 48 hours between 20 and 22 December due to a new virus variant initially discovered in Kent.
Passenger ferries and lorry freight bound for France were suspended from Dover, Portsmouth and Newhaven.
An emergency procedure devised as part of post-Brexit preparations allowed lorries to be "stacked" - leaving thousands of foreign drivers stranded throughout southern England.