Long delays are expected for anyone trying to head to Preston from the North during Tuesday lunchtime.
Emergency services have closed two lanes of the M6 southbound between Junction 33 (Lancaster South) and Junction 32 (Broughton) .
The crash is understood to involve a motorbike, lorry and a motorhome.
Delays of more than 50 minutes are being experienced following the crash which took place shortly before 12noon.
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It is not known if anyone is hurt in the crash at this stage.
Stagecoach have advised there is heavier than normal traffic on the A6 southbound due to the crash on the M6 causing drivers to find alternative routes.