Hurricane Irma threatens luxury Trump properties

Hurricane Irma has inflicted "serious damage" on Donald Trump's Caribbean mansion, according to the French government. 

The US President's $US16.9m beachfront property on the island of Saint Martin is the first of several luxury Trump properties that lie in the superstorm's path of destruction.

French Interior Minister Gérard Collomb told reporters, "We know that the four most solid buildings on the island have been destroyed which means that more rustic structures have probably been completely or partially destroyed."

Footage on social media shows roads are flooded and cars have been overturned on the 87sqm island.

Trump's 11-bedroom estate, known as the Chateau des Palmiers (Castle of Palm Trees), is owned by a trust and had been rented out.

Trump's $US175m Mar-a-Lago estate, famously dubbed the 'winter White House', could also take a hit, with Florida's Palm Beach County declaring an official state of emergency.

Several Trump-owned high-rise condominiums near Miami are also in danger.

Trump Organisation spokesperson Amanda Miller told Reuters the situation was being closely monitored.

"Our teams at the Trump properties in Florida are taking all of the proper precautions and following local and Florida state advisories very closely to ensure that everyone is kept safe and secure," Miller said.

Climate change is being blamed for Irma's intensity. The open ocean is not normally warm enough for hurricanes to form, but Irma is over water that is one degree Celsius warmer than usual.

President Trump, who withdrew the US from the Paris climate accord in June, has long refused to acknowledge the existence of climate change.

He has called it "nonexistent," "mythical" and a "total con job" in the past, as well as seeming to believe it is a Chinese hoax.

Singer Nancy Sinatra had this to say: