Gateshead Council says people are "putting their lives at risk" by ignoring the emergency footpath closure on Keelman's Way.
A section of the path, near Wylam, had to be closed after a landslip earlier this month.
There are still concerns it could collapse and barriers have been put up to stop people using the walkway.
The council has now erected heavy fencing in a bid to stop people using the area.
The collapsed section of riverbank is privately-owned and the council is in communication with the landowners to discuss the restoration of the riverbank and the reopening of the Keelman’s Way.
The Environment Agency would need to give permission for any works affecting the River Tyne. Gateshead Council is also in contact with the team there.