The incident is causing delays as Highways England staff are at the scene attempting to clean up the spill on the M62 Eastbound at Junction 29 (Lofthouse).
A spokesman for Highways North East said: "Traffic has been temporarily stopped on the #M62 eastbound at J29 while the exit slip road is closed for diesel spill clear-up.
"Please be patient we'll get you moving again as soon as possible."
The diesel spill happened following a collision on the road.
The fast link onto the the M1 north remains open. For M1 south, continue to J30 and turn around or exit at J28 and use the A650.