Cargo, such as wood and scrap metal, has fallen from the ferry

The ship, which is listing at about 50 degrees, has turned into a tourist attraction since running aground on Blackpool beach on Thursday.

HM Coastguard said onlookers straying too close during the salvage operation were putting themselves in danger.

Lancashire Police said they would step in to help the private security firm maintaining the 400m exclusion zone.

The Riverdance had been heading from Warrenpoint, County Down, to Heysham, Lancashire, last week when it was hit by a freak wave.

Twenty-three people were lifted to safety, including 19 crew and four passengers.

The area remains dangerous and unstable so people must remain cautious Insp Tim Newton, Lancashire Police

A salvage team is still working to refloat the vessel, which is carrying almost 1,200 tonnes of freight in lorry trailers and containers.

Concerns have been raised after sightseers were seen posing for photographs next to the angled ferry.

"They're walking out along the sand at low water," a coastguard spokesman said.

A spokesman for Seatruck Ferries, which owns the ship, said the ship moved in high tide on Monday, causing about six containers to fall off.

Lancashire Police are providing assistance to the salvage operation and are warning the public to stay clear and use a section of the promenade set aside for people to watch from a safe distance.

Salvage continues

Insp Tim Newton, of Lancashire Constabulary, said: "We've had huge numbers of visitors over the last week to see the spectacle.

"We have been working closely with the Maritime and Coastguard Agency to facilitate the salvage operation and prevent people going onto the sand and out to the vessel.

"The area remains dangerous and unstable so people must remain cautious."

Anyone found in breach of the cordon will be asked to move on and if this request is refused, police say they could be issued with a fine.

If a person refuses to give details they will risk being arrested, the force said.

Salvage equipment is being lifted by crane on to the Riverdance in a bid to pump water into the empty ballast tanks to reduce the list.