PARIS, France (AFP) — The French government is preparing a plan to deal with a new invasion of stinky seaweed that is covering the beaches of some its islands in the Caribbean, causing health problems for residents and threatening key fishing and tourism industries.

The brown sargassum algae “is one more disaster for the West Indies, one which we here probably haven’t fully taken into account,” Environment Minister Nicolas Hulot told lawmakers in Paris late Wednesday.

Tons of the seaweed began arriving on the islands of Martinique and Guadeloupe several weeks ago, where it has piled up knee deep in some areas over large stretches of shoreline.

It soon begins decaying, producing huge amounts of hydrogen sulphide and other noxious gases which reek of ammonia or rotten eggs and can severely irritate the eyes, nose and throat.

The fumes also damage nearby houses and other property by eating away at metal, while also killing fish and fauna, hurting the local fishing industry.

Officials have closed schools near infested zones, while some islands have been cut off since supply boats and ferries cannot get past the thick banks of seaweed.

The French government has already unlocked three million euros (US$3.5 million) of credits for supplying tractors, gas masks and other equipment to remove the seaweed — though it often returns in a matter of weeks.

“Beyond the urgent response, a new national plan for combatting sargassum will be finalised by mid-June,” Hulot said in parliament.

Although researchers are not sure why the seaweed suddenly begins proliferating in the region, “climate change is probably aggravating the problem,” Hulot said.

Similar outbreaks have occurred in the Caribbean in recent years, often requiring officials to deploy the army to gather up the seaweed.

But officials then need to figure out what to do with it, since the fumes are so toxic that the algae cannot be used for producing biomass fuel, nor can it be turned into fertiliser.

Currently the only option is to spread it out across acres of isolated land until it fully decays and dries out.

This latest invasion comes as Guadeloupe, Martinique and other French islands are still rebuilding from devastating hurricanes that struck the Caribbean last September, causing millions of euros in damages.