Congealed blocks of palm oil the size of boulders have washed up on to beaches along the coasts of the south and south west posing a risk to children and animals.
The deposits, which look like candle wax and can smell rotten, have been found in Brighton in East Sussex and have previously washed up in Hampshire, Kent, Devon and Cornwall.
A spokesman for Brighton and Hove City Council advised dog walkers to take care saying that if eaten, the palm oil could make their pets very ill.
He said: “We’re asking dog owners and dog walkers to keep a close eye on their dogs on local beaches.
“Small amounts of suspected solidified palm oil have washed up on local beaches in Brighton & Hove. The palm oil deposits are white lumps that look a bit like candle wax and can smell rotten.
“Dogs will often eat it if given the chance but this can make them very ill.
“Our seafront and cleansing teams are working together to spot and dispose of the palm oil and have put up temporary signs alerting dog walkers to the possible danger.
“Much larger amounts of suspected palm oil have washed up recently on Rottingdean, Lancing and Shoreham beaches.”
A Cornwall Council spokesman explained that palm oil is a natural, edible vegetable which can be used in food processing but can become a problem when released legally by ships at sea.
He said: “Whilst on the ships, and whilst in the sea, palm oil can become contaminated with other waste products and because its edible it can be attractive to some animals who can become ill after coming into contact with it.”
The council previously released advice stating: “If you’re heading to the beach please take care - while the substance has been described as non-toxic, given the reports about dogs becoming ill, we’d suggest keeping children and pets away from the deposits. And if you come into contact with the substance, wash it off with soap or shower gel and wash your clothes.”