The SS Richard Montgomery sank in the Thames Estuary in August 1944, coming to rest at a depth of 49ft with 1,400 tonnes of explosives still in her hold.
The Department for Transport wants to trim the SS Richard Montgomery masts as it is feared they could fall on to the shipwreck below and cause a detonation.
It is feared that the unexploded ordnance could cause mass damage and loss of life after it was revealed an explosion could cause a 15ft high tsunami tidal wave.
Three fishermen were rescued from their yacht when they drifted dangerously close to a shipwreck packed with 1,400 tonnes of explosives.
The 27ft vessel was floating near the mouth of the Medway Estuary in Kent, close to where the wreck of the SS Richard Montgomery lies beneath the surface.
Lifeboat crew were sent from Sheerness in Kent to help the yacht and those on board and a tow rope was then fixed to pull it to safety.
The SS Richard Montgomery is feared to have enough remaining munitions on board to cause a massive 1.4 kiloton explosion which could lead to a four-foot tidal wave in the Thames estuary.