There were no signs of protesters at Shell's Stanlow oil refinery in Ellesmere Port, Cheshire.
Officers from Cheshire Constabulary kept a low profile and security guards were checking drivers passes as they approached the road to the main gate.
A spokesman for the force said: We received no specific intelligence of any protests but we have officers on scene as a precaution.
Two people did turn up earlier on foot, and they were allowed to go to the main gate because they were not in vehicles. They left shortly afterwards.
There has been no sign of protesters in vehicles.
A blockade of Stanlow in September 2000 sparked the nationwide protests.
Organisers of the original Stanlow protest had condemned suggested plans for a similar blockade this week.
North Wales haulage firm boss Dai Owen said: A blockade would not receive the support of the public. It is not a good idea, and I dont think it will happen.