Motorists are complaining of gridlock after a motorway was closed for the building of a new junction.
The M20 in Kent is shut until 06:00 GMT on Monday between junctions 9 and 11 coast-bound and junctions 11 and 10 London-bound,
Traffic to both the Port of Dover and Eurotunnel terminal at Folkestone is facing severe delays.
Highways England said drivers were using the A20 rather than following the official M2 diversion.
Traffic to both the Port of Dover and Eurotunnel terminal at Folkestone is being affected by the closure.
James Evans tweeted: “There is clearly an issue as Sat Nav and google maps are not showing any diversions and saying stay on the M20. Total gridlock and an extra 90 minutes to get to Eurotunnel.”
Motorists have complained that the gridlock on the A20 is due to temporary traffic lights.
Wayne tweeted: “If you live or work in the area, the A20 is the only viable route. So why not co ordinate with your fellow agencies to get temp lights lifted? Or delay the m20 closure. Or is that too simple?”
Highways England said the A20 was not part of the official diversion route.
The agency tweeted: “Unfortunately many vehicles are self diverting via the A20. We’re liaising with the relevant parties and doing our best to encourage traffic not to do this.”
A spokesman for Highways England said: “Highways England is creating a brand new motorway junction for Ashford – the M20 Junction 10A – and will install the major components of two new bridges over two weekends in January.
“The bridges will form the two sides of the new junction roundabout, carrying traffic over the motorway.”
Westbound traffic is diverted via the M20, A29, A2, M2, A249. The eastbound diversion follows the M25, A2, M2, A20 and M20.
The Port of Dover is also warning motorists of severe delays on the A20 and asked them to use the official diversion via the M2, rather than the A20.