Warning signs have been erected at various parts of a stunning stretch of coastline after sump holes and quicksand appeared.
The notices have gone up along Druridge Bay beach and the public is being urged to avoid these areas at the current time.
The holes have appeared at Hadston Carrs, as well as to the north of Hauxley Nature Reserve, between Silver Carrs and Hauxley Haven.
Northumberland County Council is speaking to the Coal Authority to see if the situation could be related to mining.
A county council spokeswoman said: “We are aware of some sump holes and areas of quicksand that have appeared in parts of the beach at Druridge Bay.
“We have erected warning signs to make members of the public aware and to ask them to avoid the areas at the current time.
“As they are due to rising water and are between the high and low tide marks there is little that we can do to alleviate the situation, however we will be monitoring the areas closely.
“We are also liaising with the Coal Authority to see if the holes could be mining related, and if so, whether they can provide any relevant information or advice.”
The holes have been the topic of conversation on social media, with numerous people warning beach-goers to stay away from these areas, especially dog walkers.