The lorry overturned at around 2.30am and a large amount of diesel and oil has spilled onto the carriageway.
This will need to be cleared and the road surface inspected for damage before the motorway can be reopened.
According to National Highways, the northbound carriageway of the motorway is expected to remain closed until around 10.30am.
Drivers are advised to follow the hollow circle diversion symbols on road signs for the following diversion route.
- Exit M6 J32 (Blackpool), onto M55
- Follow M55 westbound to J1 Exit M55 at J1 (Broughton) and take third roundabout exit, A6 Garstang
- Follow A6 northbound through Broughton, Barton, Bilsborrow, Garstang, to M6 J33 (Lancaster South), rejoin M6 northbound