Macron's plane touched down in Saint Martin as anger grew over looting and lawlessness in the French-Dutch territory after Hurricane Irma.
Speaking in Guadeloupe earlier, Macron said the government began preparing "one of the biggest airlifts since World War II" days before Irma hit on Wednesday.
"Now is not the time for controversy," he said, adding: "Returning life to normal is the absolute priority."
The French, British and Dutch governments have faced criticism for failing to anticipate the disaster, with an editorial in The Telegraph newspaper calling the response "appallingly slow."
Touring Saint Martin, Macron was at times jeered by people waiting for aid supplies or hoping to catch flights for France in order to escape the devastation across the island.
"We've been here since six in the morning and we're still waiting, under a blazing sun," said one woman in a crowd of people hoping to leave as soon as possible.
Another woman asked: "Why are you here?"
But Macron said that "everybody who wants to leave will be able to," with officials saying that about 2,000 of the 35,000 residents on the French side of Saint Martin had already left in recent days.
British Foreign Secretary Boris Johnson arrived Tuesday in Bridgetown, the capital of Barbados, where he met with some of the nearly 1,000 military personnel sent to bolster relief efforts and security.
He was also expected to visit the British Virgin Islands and Anguilla.
"The UK is going to be with you for the long term," Johnson had told residents in a video message.
He has dismissed the criticism as "completely unjustified," calling the relief effort "unprecedented."
A mother picking up her daughter, a survivor who flew to Paris on Monday, said government help was non-existent on Saint Martin.
"They gave us phone numbers but they didn't work. Only social media and solidarity worked," said the woman, who spoke on condition of anonymity.
"People were left to their own devices. They had to set up militias and take turns defending themselves" against looters, she said.
"All the gangs came to the French side... with guns and machetes. It's unbelievably chaotic."
Macron, who is due to visit Saint Barthelemy Wednesday, said he wanted to "disarm" St. Martin.
"There is an endemic problem on the island, that preexisted this crisis, which is weapons," he said. "It's a challenge we must face."
'Expensive legacy of empire'
The British Overseas Territories in the Caribbean are highly dependent on aid, making them what The Times called "an expensive legacy of empire."
In France, opposition figures have accused Macron's fledgling government of bungling the response to the disaster.
Radical leftist Jean-Luc Melenchon has called for a parliamentary inquiry and far-right leader Marine Le Pen said the government had left islanders to "fend for themselves."
There has also been criticism of the Dutch response.
"They reacted far too late. The French were much quicker on Saint Martin to evacuate people," tourist Kitty Algra told Dutch newspaper AD.