The National Trust has concerns about possible coastal oil spills from tankers, despite government assurances.
Transport Minister Mike Penning plans to allow ship-to-ship oil transfers off the coast of Suffolk saying "it will be very strictly controlled".
The National Trust claims small spills often go unreported.
"We are concerned there could be damage to this important habitat should the worst happen," said Martin Atkinson, National Trust property manager.
New government legislation proposes to have a single designated area for out-of-harbour transfers in the UK.
It would be inside the UK's territorial waters off the Suffolk coast and regulated with a permit system.
John Perkins, secretary of the Southwold and Reydon Society, said it was a "disaster waiting to happen".
Mr Perkins said: "You've got dozens of fairly poorly maintained Russian oil tankers with 10,000 to 30,000 gallons on board and the law of averages will tell you that whatever precautions somebody takes, you are going to get an accident.
"There are 30,000 jobs in Suffolk that depend on tourism and if suddenly all of your coastline is covered in oil, who is going to come here?"
Mr Penning, parliamentary under-secretary of state for transport, said: "The previous government had attempted to ban any ship-to-ship.
"But actually, what they were going to do was push it all 12.1 miles offshore, so we had no control over them at all.
"What we've got now is legislation in place which will protect the environment and allow the industry to safely do the work they need to do."
'Long way away'
The National Trust owns Orford Ness and Dunwich Heath on the Suffolk coast and it said there had not been proper consultation.
Mr Atkinson said: "We certainly welcome regulation of this, but small spills are often not dealt with particularly well.
"If we do have a spill, we've heard that the response materials are quite a long way away."
Mr Perkins added: "There's nothing to stop them going 12 miles out and doing whatever they want without supervision."