Police closed the M23 northbound at junction 11 near Pease Pottage due to a lorry fire at 4.10pm today (Wednesday 22 May).
The Highways Agency have put diversions in place but the incident near Pease Pottage is causing significant traffic delays in the area.
Lane three of the M23 northbound has been re-opened and the southbound lane is flowing.
Travelling times to Gatwick Airport are being affected but drivers can rejoin the road at junctions 10 and 10A.
Once fire and rescue have moved their vehicles, it is hoped lane two northbound will also re-open shortly.
The lorry driver was not hurt.
There has been resulting congestion on the A23 up to Handcross.