Officers were called to concern for safety between junction eight and junction nine near Gatwick at around 6am today (September 10).
Traffic was held in both directions but the northbound carriageway was reopened just after 8am.
Two lanes are still closed near the M25 Interchange which is causing long delays in the area.
Police are continuing to ask motorists to avoid the M23 as the incident is being dealt with.
A spokesperson for London Gatwick said: “Passengers driving to London Gatwick are advised to leave more to time to reach the airport this morning.”
The full statement from Surrey Police says: “Lanes 3 and 4 are now open on the M23 southbound between junctions 8 and 9. Lanes 1 and 2 remain closed. The northbound carriageway was reopened shortly after 8am.
“Police were called to a concern for safety on the M23 between junctions 8 and 9 just after 6am this morning (10 September).
“Officers are still on scene, and the road is currently closed in both directions. We are asking people to avoid the area at this time.
“Thank you for your patience, we will update in due course.”
