Marine Drive is closed in both directions between Southport Pier and the Esplanade roundabout, due to a lorry having collided with the pier.
Traffic will be diverted over Marine Way Bridge and onto the Promenade.
Access only to Ocean Plaza car park.
The road remains closed with safety inspections to the pier being carried out to see if any serious damage has been done.
The Grade II listed Southport Pier is the oldest iron pier in the country, standing for over 150 years.