"It's an enormous catastrophe. Ninety-five percent of the island is destroyed. I'm in shock. It's frightening," said Gibbs, a former French lawmaker, speaking on Radio Caribbean International.
The island is in need of emergency assistance, he said. "I have sick people to evacuate, I have a population to evacuate because I don't know where I can shelter them," he said.
At least eight people have been killed in the French part of St Martin, Colonel Vincent Boichard, head of a public safety mission said.
Hurricane Irma, one of the most powerful Atlantic storms on record, cut a deadly swath through a string of small Caribbean islands on Wednesday.
The French minister for overseas affairs, Annick Girardin, was to fly to Guadeloupe late Wednesday with emergency teams and supplies to assess the situation, the ministry said.
"It's too soon for casualty figures [but] I can already tell you the toll will be harsh and cruel," French President Macron said, adding that he expected damage on St Barts and St Martin to be "considerable".
St Martin, located south of the island of Anguilla, is divided between the Netherlands and France.
St Barts ("Saint Barthelemy" in French), which lies to the southeast of St Martin, is administered with the status of a French collectivity, as is the French part of St Martin.
- with AFP